diff --git a/api4/post.go b/api4/post.go
index 3b356a49a3..d952408afa 100644
--- a/api4/post.go
+++ b/api4/post.go
@@ -756,7 +756,7 @@ func setPostUnread(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	state, err := c.App.MarkChannelAsUnreadFromPost(c.Params.PostId, c.Params.UserId, collapsedThreadsSupported, false)
+	state, err := c.App.MarkChannelAsUnreadFromPost(c.Params.PostId, c.Params.UserId, collapsedThreadsSupported)
 	if err != nil {
 		c.Err = err
 		return
diff --git a/app/app_iface.go b/app/app_iface.go
index 72f99abd56..c2bf38bd52 100644
--- a/app/app_iface.go
+++ b/app/app_iface.go
@@ -223,7 +223,7 @@ type AppIface interface {
 	// MakeAuditRecord creates a audit record pre-populated with defaults.
 	MakeAuditRecord(event string, initialStatus string) *audit.Record
 	// MarkChanelAsUnreadFromPost will take a post and set the channel as unread from that one.
-	MarkChannelAsUnreadFromPost(postID string, userID string, collapsedThreadsSupported, followThread bool) (*model.ChannelUnreadAt, *model.AppError)
+	MarkChannelAsUnreadFromPost(postID string, userID string, collapsedThreadsSupported bool) (*model.ChannelUnreadAt, *model.AppError)
 	// MentionsToPublicChannels returns all the mentions to public channels,
 	// linking them to their channels
 	MentionsToPublicChannels(message, teamID string) model.ChannelMentionMap
@@ -1035,7 +1035,6 @@ type AppIface interface {
 	TriggerWebhook(c *request.Context, payload *model.OutgoingWebhookPayload, hook *model.OutgoingWebhook, post *model.Post, channel *model.Channel)
 	UnregisterPluginCommand(pluginID, teamID, trigger string)
 	UpdateActive(c *request.Context, user *model.User, active bool) (*model.User, *model.AppError)
-	UpdateChannelLastViewedAt(channelIDs []string, userID string) *model.AppError
 	UpdateChannelMemberNotifyProps(data map[string]string, channelID string, userID string) (*model.ChannelMember, *model.AppError)
 	UpdateChannelMemberRoles(channelID string, userID string, newRoles string) (*model.ChannelMember, *model.AppError)
 	UpdateChannelMemberSchemeRoles(channelID string, userID string, isSchemeGuest bool, isSchemeUser bool, isSchemeAdmin bool) (*model.ChannelMember, *model.AppError)
diff --git a/app/channel.go b/app/channel.go
index ec9fcd29c8..362bb763d4 100644
--- a/app/channel.go
+++ b/app/channel.go
@@ -2486,28 +2486,6 @@ func (a *App) SetActiveChannel(userID string, channelID string) *model.AppError
 	return nil
 }
 
-func (a *App) UpdateChannelLastViewedAt(channelIDs []string, userID string) *model.AppError {
-	if _, err := a.Srv().Store.Channel().UpdateLastViewedAt(channelIDs, userID, *a.Config().ServiceSettings.ThreadAutoFollow); err != nil {
-		var invErr *store.ErrInvalidInput
-		switch {
-		case errors.As(err, &invErr):
-			return model.NewAppError("UpdateChannelLastViewedAt", "app.channel.update_last_viewed_at.app_error", nil, invErr.Error(), http.StatusBadRequest)
-		default:
-			return model.NewAppError("UpdateChannelLastViewedAt", "app.channel.update_last_viewed_at.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-	}
-
-	if *a.Config().ServiceSettings.EnableChannelViewedMessages {
-		for _, channelID := range channelIDs {
-			message := model.NewWebSocketEvent(model.WebsocketEventChannelViewed, "", "", userID, nil)
-			message.Add("channel_id", channelID)
-			a.Publish(message)
-		}
-	}
-
-	return nil
-}
-
 func (a *App) IsCRTEnabledForUser(userID string) bool {
 	if *a.Config().ServiceSettings.CollapsedThreads == model.CollapsedThreadsDisabled {
 		return false
@@ -2521,7 +2499,7 @@ func (a *App) IsCRTEnabledForUser(userID string) bool {
 }
 
 // MarkChanelAsUnreadFromPost will take a post and set the channel as unread from that one.
-func (a *App) MarkChannelAsUnreadFromPost(postID string, userID string, collapsedThreadsSupported, followThread bool) (*model.ChannelUnreadAt, *model.AppError) {
+func (a *App) MarkChannelAsUnreadFromPost(postID string, userID string, collapsedThreadsSupported bool) (*model.ChannelUnreadAt, *model.AppError) {
 	if !collapsedThreadsSupported || !a.IsCRTEnabledForUser(userID) {
 		return a.markChannelAsUnreadFromPostCRTUnsupported(postID, userID)
 	}
@@ -2553,23 +2531,15 @@ func (a *App) MarkChannelAsUnreadFromPost(postID string, userID string, collapse
 		if storeErr != nil && !errors.As(storeErr, &nfErr) {
 			return nil, model.NewAppError("MarkChannelAsUnreadFromPost", "app.channel.update_last_viewed_at_post.app_error", nil, storeErr.Error(), http.StatusInternalServerError)
 		}
-		var opts store.ThreadMembershipOpts
 		// if this post was not followed before, create thread membership and update mention count
 		if threadMembership == nil {
-			opts = store.ThreadMembershipOpts{
-				Following:             followThread,
+			opts := store.ThreadMembershipOpts{
+				Following:             false,
 				IncrementMentions:     false,
 				UpdateFollowing:       true,
 				UpdateViewedTimestamp: true,
 				UpdateParticipants:    false,
 			}
-		} else if !threadMembership.Following && followThread {
-			opts = store.ThreadMembershipOpts{
-				Following:       true,
-				UpdateFollowing: true,
-			}
-		}
-		if opts.UpdateFollowing || threadMembership == nil {
 			threadMembership, storeErr = a.Srv().Store.Thread().MaintainMembership(user.Id, threadId, opts)
 			if storeErr != nil && !errors.As(storeErr, &nfErr) {
 				return nil, model.NewAppError("MarkChannelAsUnreadFromPost", "app.channel.update_last_viewed_at_post.app_error", nil, storeErr.Error(), http.StatusInternalServerError)
@@ -2608,7 +2578,7 @@ func (a *App) MarkChannelAsUnreadFromPost(postID string, userID string, collapse
 		}
 	}
 
-	channelUnread, nErr := a.Srv().Store.Channel().UpdateLastViewedAtPost(post, userID, unreadMentions, unreadMentionsRoot, *a.Config().ServiceSettings.ThreadAutoFollow, true)
+	channelUnread, nErr := a.Srv().Store.Channel().UpdateLastViewedAtPost(post, userID, unreadMentions, unreadMentionsRoot, true)
 	if nErr != nil {
 		return channelUnread, model.NewAppError("MarkChannelAsUnreadFromPost", "app.channel.update_last_viewed_at_post.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 	}
@@ -2644,7 +2614,7 @@ func (a *App) markChannelAsUnreadFromPostCRTUnsupported(postID string, userID st
 	// In CRT Supported Client: badge on channel only sums mentions in root posts including and below the post that was marked.
 	// In CRT Unsupported Client: badge on channel sums mentions in all posts (root & replies) including and below the post that was marked unread.
 	if post.RootId == "" {
-		channelUnread, nErr := a.Srv().Store.Channel().UpdateLastViewedAtPost(post, userID, unreadMentions, unreadMentionsRoot, false, true)
+		channelUnread, nErr := a.Srv().Store.Channel().UpdateLastViewedAtPost(post, userID, unreadMentions, unreadMentionsRoot, true)
 		if nErr != nil {
 			return channelUnread, model.NewAppError("MarkChannelAsUnreadFromPost", "app.channel.update_last_viewed_at_post.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 		}
@@ -2718,7 +2688,7 @@ func (a *App) markChannelAsUnreadFromPostCRTUnsupported(postID string, userID st
 		}
 	}
 
-	channelUnread, nErr := a.Srv().Store.Channel().UpdateLastViewedAtPost(post, userID, unreadMentions, 0, false, false)
+	channelUnread, nErr := a.Srv().Store.Channel().UpdateLastViewedAtPost(post, userID, unreadMentions, 0, false)
 	if nErr != nil {
 		return channelUnread, model.NewAppError("MarkChannelAsUnreadFromPost", "app.channel.update_last_viewed_at_post.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 	}
diff --git a/app/channel_test.go b/app/channel_test.go
index 070bc20be8..889e8675e3 100644
--- a/app/channel_test.go
+++ b/app/channel_test.go
@@ -1274,16 +1274,16 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 	unread, err = th.App.GetChannelUnread(c1.Id, u2.Id)
 	require.Nil(t, err)
 	require.Equal(t, int64(4), unread.MsgCount)
-	err = th.App.UpdateChannelLastViewedAt([]string{c1.Id, pc1.Id}, u1.Id)
+	_, err = th.App.MarkChannelsAsViewed([]string{c1.Id, pc1.Id}, u1.Id, "", false)
 	require.Nil(t, err)
-	err = th.App.UpdateChannelLastViewedAt([]string{c1.Id, pc1.Id}, u2.Id)
+	_, err = th.App.MarkChannelsAsViewed([]string{c1.Id, pc1.Id}, u2.Id, "", false)
 	require.Nil(t, err)
 	unread, err = th.App.GetChannelUnread(c1.Id, u2.Id)
 	require.Nil(t, err)
 	require.Equal(t, int64(0), unread.MsgCount)
 
 	t.Run("Unread but last one", func(t *testing.T) {
-		response, err := th.App.MarkChannelAsUnreadFromPost(p2.Id, u1.Id, true, true)
+		response, err := th.App.MarkChannelAsUnreadFromPost(p2.Id, u1.Id, true)
 		require.Nil(t, err)
 		require.NotNil(t, response)
 		assert.Equal(t, int64(2), response.MsgCount)
@@ -1294,7 +1294,7 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 	})
 
 	t.Run("Unread last one", func(t *testing.T) {
-		response, err := th.App.MarkChannelAsUnreadFromPost(p3.Id, u1.Id, true, true)
+		response, err := th.App.MarkChannelAsUnreadFromPost(p3.Id, u1.Id, true)
 		require.Nil(t, err)
 		require.NotNil(t, response)
 		assert.Equal(t, int64(3), response.MsgCount)
@@ -1305,7 +1305,7 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 	})
 
 	t.Run("Unread first one", func(t *testing.T) {
-		response, err := th.App.MarkChannelAsUnreadFromPost(p1.Id, u1.Id, true, true)
+		response, err := th.App.MarkChannelAsUnreadFromPost(p1.Id, u1.Id, true)
 		require.Nil(t, err)
 		require.NotNil(t, response)
 		assert.Equal(t, int64(1), response.MsgCount)
@@ -1322,7 +1322,7 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 	})
 
 	t.Run("Unread on a private channel", func(t *testing.T) {
-		response, err := th.App.MarkChannelAsUnreadFromPost(pp1.Id, u1.Id, true, true)
+		response, err := th.App.MarkChannelAsUnreadFromPost(pp1.Id, u1.Id, true)
 		require.Nil(t, err)
 		require.NotNil(t, response)
 		assert.Equal(t, int64(0), response.MsgCount)
@@ -1331,7 +1331,7 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 		assert.Equal(t, int64(2), unread.MsgCount)
 		assert.Equal(t, pp1.CreateAt-1, response.LastViewedAt)
 
-		response, err = th.App.MarkChannelAsUnreadFromPost(pp2.Id, u1.Id, true, true)
+		response, err = th.App.MarkChannelAsUnreadFromPost(pp2.Id, u1.Id, true)
 		assert.Nil(t, err)
 		assert.Equal(t, int64(1), response.MsgCount)
 		unread, err = th.App.GetChannelUnread(pc1.Id, u1.Id)
@@ -1360,7 +1360,7 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 			Message:   "@" + u1.Username,
 		}, c2, false, true)
 
-		response, err := th.App.MarkChannelAsUnreadFromPost(p4.Id, u1.Id, true, true)
+		response, err := th.App.MarkChannelAsUnreadFromPost(p4.Id, u1.Id, true)
 		assert.Nil(t, err)
 		assert.Equal(t, int64(1), response.MsgCount)
 		assert.Equal(t, int64(2), response.MentionCount)
@@ -1383,7 +1383,7 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 		_, err := th.App.CreatePost(th.Context, &model.Post{ChannelId: dc.Id, UserId: th.BasicUser.Id, Message: "testReply", RootId: dm1.Id}, dc, false, false)
 		assert.Nil(t, err)
 
-		response, err := th.App.MarkChannelAsUnreadFromPost(dm1.Id, u2.Id, true, true)
+		response, err := th.App.MarkChannelAsUnreadFromPost(dm1.Id, u2.Id, true)
 		assert.Nil(t, err)
 		assert.Equal(t, int64(0), response.MsgCount)
 		assert.Equal(t, int64(4), response.MentionCount)
@@ -1397,7 +1397,7 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 	})
 
 	t.Run("Can't unread an imaginary post", func(t *testing.T) {
-		response, err := th.App.MarkChannelAsUnreadFromPost("invalid4ofngungryquinj976y", u1.Id, true, true)
+		response, err := th.App.MarkChannelAsUnreadFromPost("invalid4ofngungryquinj976y", u1.Id, true)
 		assert.NotNil(t, err)
 		assert.Nil(t, response)
 	})
@@ -2070,7 +2070,7 @@ func TestMarkChannelAsUnreadFromPostPanic(t *testing.T) {
 	})
 
 	require.NotPanics(t, func() {
-		th.App.MarkChannelAsUnreadFromPost("postID", "userID", true, true)
+		th.App.MarkChannelAsUnreadFromPost("postID", "userID", true)
 	}, "unexpected panic from MarkChannelAsUnreadFromPost")
 }
 
@@ -2246,7 +2246,7 @@ func TestMarkChannelAsUnreadFromPostCollapsedThreadsTurnedOff(t *testing.T) {
 	require.Nil(t, appErr)
 
 	t.Run("Mark reply post as unread", func(t *testing.T) {
-		_, err := th.App.MarkChannelAsUnreadFromPost(replyPost1.Id, th.BasicUser.Id, true, true)
+		_, err := th.App.MarkChannelAsUnreadFromPost(replyPost1.Id, th.BasicUser.Id, true)
 		require.Nil(t, err)
 		// Get channel unreads
 		// Easier to reason with ChannelUnread now, than channelUnreadAt from the previous call
@@ -2270,7 +2270,7 @@ func TestMarkChannelAsUnreadFromPostCollapsedThreadsTurnedOff(t *testing.T) {
 	})
 
 	t.Run("Mark root post as unread", func(t *testing.T) {
-		_, err := th.App.MarkChannelAsUnreadFromPost(rootPost1.Id, th.BasicUser.Id, true, true)
+		_, err := th.App.MarkChannelAsUnreadFromPost(rootPost1.Id, th.BasicUser.Id, true)
 		require.Nil(t, err)
 		// Get channel unreads
 		// Easier to reason with ChannelUnread now, than channelUnreadAt from the previous call
@@ -2285,6 +2285,14 @@ func TestMarkChannelAsUnreadFromPostCollapsedThreadsTurnedOff(t *testing.T) {
 	})
 }
 
+// TestMarkUnreadWithThreads asserts the behaviour of App.MarkChannelAsUnreadFromPost, but was
+// originally written when that API accepted a followThread parameter. While tested, that parameter
+// was never actually called as true, resulting in deadcode.
+//
+// When removing the parameter, one of the following tests failed, as it covered behaviour that
+// was unused and now unsupported. The test has since been updated to reflect the new reality,
+// but a careful examination of MarkChannelAsUnreadFromPost should be conducted as it's unclear
+// why that API tries to manipulate thread memberships at all. Fixing that is left to another task.
 func TestMarkUnreadWithThreads(t *testing.T) {
 	os.Setenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS", "true")
 	defer os.Unsetenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS")
@@ -2295,47 +2303,11 @@ func TestMarkUnreadWithThreads(t *testing.T) {
 		*cfg.ServiceSettings.CollapsedThreads = model.CollapsedThreadsDefaultOn
 	})
 
-	t.Run("Follow threads only if specified", func(t *testing.T) {
-		rootPost, appErr := th.App.CreatePost(th.Context, &model.Post{UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi"}, th.BasicChannel, false, false)
-		require.Nil(t, appErr)
-		replyPost, appErr := th.App.CreatePost(th.Context, &model.Post{RootId: rootPost.Id, UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi"}, th.BasicChannel, false, false)
-		require.Nil(t, appErr)
-		threads, appErr := th.App.GetThreadsForUser(th.BasicUser.Id, th.BasicTeam.Id, model.GetUserThreadsOpts{})
-		require.Nil(t, appErr)
-		require.Zero(t, threads.Total)
-
-		_, appErr = th.App.MarkChannelAsUnreadFromPost(replyPost.Id, th.BasicUser.Id, true, true)
-		require.Nil(t, appErr)
-
-		threads, appErr = th.App.GetThreadsForUser(th.BasicUser.Id, th.BasicTeam.Id, model.GetUserThreadsOpts{})
-		require.Nil(t, appErr)
-		require.NotZero(t, threads.Total)
-
-		threadMembership, appErr := th.App.GetThreadMembershipForUser(th.BasicUser.Id, replyPost.RootId)
-		require.Nil(t, appErr)
-		require.NotNil(t, threadMembership)
-		assert.True(t, threadMembership.Following)
-
-		// Create a new thread
-		rootPost, appErr = th.App.CreatePost(th.Context, &model.Post{UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi2"}, th.BasicChannel, false, false)
-		require.Nil(t, appErr)
-		replyPost, appErr = th.App.CreatePost(th.Context, &model.Post{RootId: rootPost.Id, UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi2"}, th.BasicChannel, false, false)
-		require.Nil(t, appErr)
-
-		_, appErr = th.App.MarkChannelAsUnreadFromPost(replyPost.Id, th.BasicUser.Id, true, false)
-		require.Nil(t, appErr)
-
-		threadMembership, appErr = th.App.GetThreadMembershipForUser(th.BasicUser.Id, replyPost.RootId)
-		require.Nil(t, appErr)
-		require.NotNil(t, threadMembership)
-		assert.False(t, threadMembership.Following)
-	})
-
 	t.Run("Set unread mentions correctly", func(t *testing.T) {
 		t.Run("Never followed root post with no replies or mentions", func(t *testing.T) {
 			rootPost, appErr := th.App.CreatePost(th.Context, &model.Post{UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi"}, th.BasicChannel, false, false)
 			require.Nil(t, appErr)
-			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true, true)
+			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true)
 			require.Nil(t, appErr)
 
 			threadMembership, appErr := th.App.GetThreadMembershipForUser(th.BasicUser.Id, rootPost.Id)
@@ -2349,7 +2321,7 @@ func TestMarkUnreadWithThreads(t *testing.T) {
 			require.Nil(t, appErr)
 			_, appErr = th.App.CreatePost(th.Context, &model.Post{RootId: rootPost.Id, UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi"}, th.BasicChannel, false, false)
 			require.Nil(t, appErr)
-			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true, true)
+			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true)
 			require.Nil(t, appErr)
 
 			threadMembership, appErr := th.App.GetThreadMembershipForUser(th.BasicUser.Id, rootPost.Id)
@@ -2363,7 +2335,7 @@ func TestMarkUnreadWithThreads(t *testing.T) {
 			require.Nil(t, appErr)
 			_, appErr = th.App.CreatePost(th.Context, &model.Post{RootId: rootPost.Id, UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi @" + th.BasicUser.Username}, th.BasicChannel, false, false)
 			require.Nil(t, appErr)
-			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true, true)
+			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true)
 			require.Nil(t, appErr)
 
 			threadMembership, appErr := th.App.GetThreadMembershipForUser(th.BasicUser.Id, rootPost.Id)
@@ -2380,7 +2352,7 @@ func TestMarkUnreadWithThreads(t *testing.T) {
 			appErr = th.App.UpdateThreadFollowForUser(th.BasicUser.Id, th.BasicTeam.Id, rootPost.Id, false)
 			require.Nil(t, appErr)
 
-			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true, true)
+			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true)
 			require.Nil(t, appErr)
 
 			threadMembership, appErr := th.App.GetThreadMembershipForUser(th.BasicUser.Id, rootPost.Id)
@@ -2399,7 +2371,7 @@ func TestMarkUnreadWithThreads(t *testing.T) {
 			appErr = th.App.UpdateThreadFollowForUser(th.BasicUser.Id, th.BasicTeam.Id, rootPost.Id, false)
 			require.Nil(t, appErr)
 
-			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true, true)
+			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true)
 			require.Nil(t, appErr)
 
 			threadMembership, appErr := th.App.GetThreadMembershipForUser(th.BasicUser.Id, rootPost.Id)
@@ -2418,13 +2390,13 @@ func TestMarkUnreadWithThreads(t *testing.T) {
 			appErr = th.App.UpdateThreadFollowForUser(th.BasicUser.Id, th.BasicTeam.Id, rootPost.Id, false)
 			require.Nil(t, appErr)
 
-			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true, true)
+			_, appErr = th.App.MarkChannelAsUnreadFromPost(rootPost.Id, th.BasicUser.Id, true)
 			require.Nil(t, appErr)
 
 			threadMembership, appErr := th.App.GetThreadMembershipForUser(th.BasicUser.Id, rootPost.Id)
 			require.Nil(t, appErr)
 			require.NotNil(t, threadMembership)
-			assert.Equal(t, int64(1), threadMembership.UnreadMentions)
+			assert.Zero(t, threadMembership.UnreadMentions)
 		})
 	})
 }
diff --git a/app/notification.go b/app/notification.go
index 46db20a8b4..1ccb9256de 100644
--- a/app/notification.go
+++ b/app/notification.go
@@ -294,7 +294,7 @@ func (a *App) SendNotifications(post *model.Post, team *model.Team, channel *mod
 		umc := make(chan *model.AppError, 1)
 		go func(userID string) {
 			defer close(umc)
-			nErr := a.Srv().Store.Channel().IncrementMentionCount(post.ChannelId, userID, *a.Config().ServiceSettings.ThreadAutoFollow, post.RootId == "")
+			nErr := a.Srv().Store.Channel().IncrementMentionCount(post.ChannelId, userID, post.RootId == "")
 			if nErr != nil {
 				umc <- model.NewAppError("SendNotifications", "app.channel.increment_mention_count.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 				return
diff --git a/app/opentracing/opentracing_layer.go b/app/opentracing/opentracing_layer.go
index bbd0d778af..40a84c534e 100644
--- a/app/opentracing/opentracing_layer.go
+++ b/app/opentracing/opentracing_layer.go
@@ -11579,7 +11579,7 @@ func (a *OpenTracingAppLayer) MakePermissionError(s *model.Session, permissions
 	return resultVar0
 }
 
-func (a *OpenTracingAppLayer) MarkChannelAsUnreadFromPost(postID string, userID string, collapsedThreadsSupported bool, followThread bool) (*model.ChannelUnreadAt, *model.AppError) {
+func (a *OpenTracingAppLayer) MarkChannelAsUnreadFromPost(postID string, userID string, collapsedThreadsSupported bool) (*model.ChannelUnreadAt, *model.AppError) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.MarkChannelAsUnreadFromPost")
 
@@ -11591,7 +11591,7 @@ func (a *OpenTracingAppLayer) MarkChannelAsUnreadFromPost(postID string, userID
 	}()
 
 	defer span.Finish()
-	resultVar0, resultVar1 := a.app.MarkChannelAsUnreadFromPost(postID, userID, collapsedThreadsSupported, followThread)
+	resultVar0, resultVar1 := a.app.MarkChannelAsUnreadFromPost(postID, userID, collapsedThreadsSupported)
 
 	if resultVar1 != nil {
 		span.LogFields(spanlog.Error(resultVar1))
@@ -15973,28 +15973,6 @@ func (a *OpenTracingAppLayer) UpdateChannel(channel *model.Channel) (*model.Chan
 	return resultVar0, resultVar1
 }
 
-func (a *OpenTracingAppLayer) UpdateChannelLastViewedAt(channelIDs []string, userID string) *model.AppError {
-	origCtx := a.ctx
-	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.UpdateChannelLastViewedAt")
-
-	a.ctx = newCtx
-	a.app.Srv().Store.SetContext(newCtx)
-	defer func() {
-		a.app.Srv().Store.SetContext(origCtx)
-		a.ctx = origCtx
-	}()
-
-	defer span.Finish()
-	resultVar0 := a.app.UpdateChannelLastViewedAt(channelIDs, userID)
-
-	if resultVar0 != nil {
-		span.LogFields(spanlog.Error(resultVar0))
-		ext.Error.Set(span, true)
-	}
-
-	return resultVar0
-}
-
 func (a *OpenTracingAppLayer) UpdateChannelMemberNotifyProps(data map[string]string, channelID string, userID string) (*model.ChannelMember, *model.AppError) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.UpdateChannelMemberNotifyProps")
diff --git a/app/post_test.go b/app/post_test.go
index 16b2757eb2..4a60735222 100644
--- a/app/post_test.go
+++ b/app/post_test.go
@@ -2314,7 +2314,7 @@ func TestCollapsedThreadFetch(t *testing.T) {
 		thread, nErr := th.App.Srv().Store.Thread().Get(postRoot.Id)
 		require.NoError(t, nErr)
 		require.Len(t, thread.Participants, 1)
-		th.App.MarkChannelAsUnreadFromPost(postRoot.Id, user1.Id, true, true)
+		th.App.MarkChannelAsUnreadFromPost(postRoot.Id, user1.Id, true)
 		l, err := th.App.GetPostsForChannelAroundLastUnread(channel.Id, user1.Id, 10, 10, true, true, false)
 		require.Nil(t, err)
 		require.Len(t, l.Order, 1)
diff --git a/model/thread.go b/model/thread.go
index e774e87a0f..8998570979 100644
--- a/model/thread.go
+++ b/model/thread.go
@@ -3,11 +3,24 @@
 
 package model
 
+// Thread tracks the metadata associated with a root post and its reply posts.
+//
+// Note that Thread metadata does not exist until the first reply to a root post.
 type Thread struct {
-	PostId       string      `json:"id"`
-	ChannelId    string      `json:"channel_id"`
-	ReplyCount   int64       `json:"reply_count"`
-	LastReplyAt  int64       `json:"last_reply_at"`
+	// PostId is the root post of the thread.
+	PostId string `json:"id"`
+
+	// ChannelId is the channel in which the thread was posted.
+	ChannelId string `json:"channel_id"`
+
+	// ReplyCount is the number of replies to the thread (excluding deleted posts).
+	ReplyCount int64 `json:"reply_count"`
+
+	// LastReplyAt is the timestamp of the most recent post to the thread.
+	LastReplyAt int64 `json:"last_reply_at"`
+
+	// Participants is a list of user ids that have replied to the thread, sorted by the oldest
+	// to newest. Note that the root post author is not included in this list until they reply.
 	Participants StringArray `json:"participants"`
 }
 
@@ -62,11 +75,37 @@ func (o *Thread) Etag() string {
 	return Etag(o.PostId, o.LastReplyAt)
 }
 
+// ThreadMembership models the relationship between a user and a thread of posts, with a similar
+// data structure as ChannelMembership.
 type ThreadMembership struct {
-	PostId         string `json:"post_id"`
-	UserId         string `json:"user_id"`
-	Following      bool   `json:"following"`
-	LastViewed     int64  `json:"last_view_at"`
-	LastUpdated    int64  `json:"last_update_at"`
-	UnreadMentions int64  `json:"unread_mentions"`
+	// PostId is the root post id of the thread in question.
+	PostId string `json:"post_id"`
+
+	// UserId is the user whose membership in the thread is being tracked.
+	UserId string `json:"user_id"`
+
+	// Following tracks whether the user is following the given thread. This defaults to true
+	// when a ThreadMembership record is created (a record doesn't exist until the user first
+	// starts following the thread), but the user can stop following or resume following at
+	// will.
+	Following bool `json:"following"`
+
+	// LastUpdated is either the creation time of the membership record, or the last time the
+	// membership record was changed (e.g. started/stopped following, viewed thread, mention
+	// count change).
+	//
+	// This field is used to constrain queries of thread memberships to those updated after
+	// a given timestamp (e.g. on websocket reconnect). It's also used as the time column for
+	// deletion decisions during any configured retention policy.
+	LastUpdated int64 `json:"last_update_at"`
+
+	// LastViewed is the last time the user viewed this thread. It is the thread analogue to
+	// the ChannelMembership's LastViewedAt and is used to decide when there are new replies
+	// for the user and where the user should start reading.
+	LastViewed int64 `json:"last_view_at"`
+
+	// UnreadMentions is the number of unseen at-mentions for the user in the given thread. It
+	// is the thread analogue to the ChannelMembership's MentionCount, and is used to highlight
+	// threads with the mention count.
+	UnreadMentions int64 `json:"unread_mentions"`
 }
diff --git a/store/opentracinglayer/opentracinglayer.go b/store/opentracinglayer/opentracinglayer.go
index fc63e95e37..41f4f326e1 100644
--- a/store/opentracinglayer/opentracinglayer.go
+++ b/store/opentracinglayer/opentracinglayer.go
@@ -1748,7 +1748,7 @@ func (s *OpenTracingLayerChannelStore) GroupSyncedChannelCount() (int64, error)
 	return result, err
 }
 
-func (s *OpenTracingLayerChannelStore) IncrementMentionCount(channelID string, userID string, updateThreads bool, isRoot bool) error {
+func (s *OpenTracingLayerChannelStore) IncrementMentionCount(channelID string, userID string, isRoot bool) error {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ChannelStore.IncrementMentionCount")
 	s.Root.Store.SetContext(newCtx)
@@ -1757,7 +1757,7 @@ func (s *OpenTracingLayerChannelStore) IncrementMentionCount(channelID string, u
 	}()
 
 	defer span.Finish()
-	err := s.ChannelStore.IncrementMentionCount(channelID, userID, updateThreads, isRoot)
+	err := s.ChannelStore.IncrementMentionCount(channelID, userID, isRoot)
 	if err != nil {
 		span.LogFields(spanlog.Error(err))
 		ext.Error.Set(span, true)
@@ -2302,7 +2302,7 @@ func (s *OpenTracingLayerChannelStore) UpdateLastViewedAt(channelIds []string, u
 	return result, err
 }
 
-func (s *OpenTracingLayerChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount int, mentionCountRoot int, updateThreads bool, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
+func (s *OpenTracingLayerChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount int, mentionCountRoot int, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ChannelStore.UpdateLastViewedAtPost")
 	s.Root.Store.SetContext(newCtx)
@@ -2311,7 +2311,7 @@ func (s *OpenTracingLayerChannelStore) UpdateLastViewedAtPost(unreadPost *model.
 	}()
 
 	defer span.Finish()
-	result, err := s.ChannelStore.UpdateLastViewedAtPost(unreadPost, userID, mentionCount, mentionCountRoot, updateThreads, setUnreadCountRoot)
+	result, err := s.ChannelStore.UpdateLastViewedAtPost(unreadPost, userID, mentionCount, mentionCountRoot, setUnreadCountRoot)
 	if err != nil {
 		span.LogFields(spanlog.Error(err))
 		ext.Error.Set(span, true)
@@ -9231,24 +9231,6 @@ func (s *OpenTracingLayerThreadStore) CollectThreadsWithNewerReplies(userId stri
 	return result, err
 }
 
-func (s *OpenTracingLayerThreadStore) Delete(postID string) error {
-	origCtx := s.Root.Store.Context()
-	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.Delete")
-	s.Root.Store.SetContext(newCtx)
-	defer func() {
-		s.Root.Store.SetContext(origCtx)
-	}()
-
-	defer span.Finish()
-	err := s.ThreadStore.Delete(postID)
-	if err != nil {
-		span.LogFields(spanlog.Error(err))
-		ext.Error.Set(span, true)
-	}
-
-	return err
-}
-
 func (s *OpenTracingLayerThreadStore) DeleteMembershipForUser(userId string, postID string) error {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.DeleteMembershipForUser")
@@ -9555,76 +9537,22 @@ func (s *OpenTracingLayerThreadStore) PermanentDeleteBatchThreadMembershipsForRe
 	return result, resultVar1, err
 }
 
-func (s *OpenTracingLayerThreadStore) Save(thread *model.Thread) (*model.Thread, error) {
+func (s *OpenTracingLayerThreadStore) UpdateLastViewedByThreadIds(userId string, threadIds []string, timestamp int64) error {
 	origCtx := s.Root.Store.Context()
-	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.Save")
+	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.UpdateLastViewedByThreadIds")
 	s.Root.Store.SetContext(newCtx)
 	defer func() {
 		s.Root.Store.SetContext(origCtx)
 	}()
 
 	defer span.Finish()
-	result, err := s.ThreadStore.Save(thread)
+	err := s.ThreadStore.UpdateLastViewedByThreadIds(userId, threadIds, timestamp)
 	if err != nil {
 		span.LogFields(spanlog.Error(err))
 		ext.Error.Set(span, true)
 	}
 
-	return result, err
-}
-
-func (s *OpenTracingLayerThreadStore) SaveMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error) {
-	origCtx := s.Root.Store.Context()
-	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.SaveMembership")
-	s.Root.Store.SetContext(newCtx)
-	defer func() {
-		s.Root.Store.SetContext(origCtx)
-	}()
-
-	defer span.Finish()
-	result, err := s.ThreadStore.SaveMembership(membership)
-	if err != nil {
-		span.LogFields(spanlog.Error(err))
-		ext.Error.Set(span, true)
-	}
-
-	return result, err
-}
-
-func (s *OpenTracingLayerThreadStore) SaveMultiple(thread []*model.Thread) ([]*model.Thread, int, error) {
-	origCtx := s.Root.Store.Context()
-	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.SaveMultiple")
-	s.Root.Store.SetContext(newCtx)
-	defer func() {
-		s.Root.Store.SetContext(origCtx)
-	}()
-
-	defer span.Finish()
-	result, resultVar1, err := s.ThreadStore.SaveMultiple(thread)
-	if err != nil {
-		span.LogFields(spanlog.Error(err))
-		ext.Error.Set(span, true)
-	}
-
-	return result, resultVar1, err
-}
-
-func (s *OpenTracingLayerThreadStore) Update(thread *model.Thread) (*model.Thread, error) {
-	origCtx := s.Root.Store.Context()
-	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.Update")
-	s.Root.Store.SetContext(newCtx)
-	defer func() {
-		s.Root.Store.SetContext(origCtx)
-	}()
-
-	defer span.Finish()
-	result, err := s.ThreadStore.Update(thread)
-	if err != nil {
-		span.LogFields(spanlog.Error(err))
-		ext.Error.Set(span, true)
-	}
-
-	return result, err
+	return err
 }
 
 func (s *OpenTracingLayerThreadStore) UpdateMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error) {
@@ -9645,24 +9573,6 @@ func (s *OpenTracingLayerThreadStore) UpdateMembership(membership *model.ThreadM
 	return result, err
 }
 
-func (s *OpenTracingLayerThreadStore) UpdateUnreadsByChannel(userId string, changedThreads []string, timestamp int64, updateViewedTimestamp bool) error {
-	origCtx := s.Root.Store.Context()
-	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.UpdateUnreadsByChannel")
-	s.Root.Store.SetContext(newCtx)
-	defer func() {
-		s.Root.Store.SetContext(origCtx)
-	}()
-
-	defer span.Finish()
-	err := s.ThreadStore.UpdateUnreadsByChannel(userId, changedThreads, timestamp, updateViewedTimestamp)
-	if err != nil {
-		span.LogFields(spanlog.Error(err))
-		ext.Error.Set(span, true)
-	}
-
-	return err
-}
-
 func (s *OpenTracingLayerTokenStore) Cleanup(expiryTime int64) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "TokenStore.Cleanup")
diff --git a/store/retrylayer/retrylayer.go b/store/retrylayer/retrylayer.go
index 08ce43db17..4202dadbcd 100644
--- a/store/retrylayer/retrylayer.go
+++ b/store/retrylayer/retrylayer.go
@@ -1975,11 +1975,11 @@ func (s *RetryLayerChannelStore) GroupSyncedChannelCount() (int64, error) {
 
 }
 
-func (s *RetryLayerChannelStore) IncrementMentionCount(channelID string, userID string, updateThreads bool, isRoot bool) error {
+func (s *RetryLayerChannelStore) IncrementMentionCount(channelID string, userID string, isRoot bool) error {
 
 	tries := 0
 	for {
-		err := s.ChannelStore.IncrementMentionCount(channelID, userID, updateThreads, isRoot)
+		err := s.ChannelStore.IncrementMentionCount(channelID, userID, isRoot)
 		if err == nil {
 			return nil
 		}
@@ -2548,11 +2548,11 @@ func (s *RetryLayerChannelStore) UpdateLastViewedAt(channelIds []string, userID
 
 }
 
-func (s *RetryLayerChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount int, mentionCountRoot int, updateThreads bool, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
+func (s *RetryLayerChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount int, mentionCountRoot int, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
 
 	tries := 0
 	for {
-		result, err := s.ChannelStore.UpdateLastViewedAtPost(unreadPost, userID, mentionCount, mentionCountRoot, updateThreads, setUnreadCountRoot)
+		result, err := s.ChannelStore.UpdateLastViewedAtPost(unreadPost, userID, mentionCount, mentionCountRoot, setUnreadCountRoot)
 		if err == nil {
 			return result, nil
 		}
@@ -10540,27 +10540,6 @@ func (s *RetryLayerThreadStore) CollectThreadsWithNewerReplies(userId string, ch
 
 }
 
-func (s *RetryLayerThreadStore) Delete(postID string) error {
-
-	tries := 0
-	for {
-		err := s.ThreadStore.Delete(postID)
-		if err == nil {
-			return nil
-		}
-		if !isRepeatableError(err) {
-			return err
-		}
-		tries++
-		if tries >= 3 {
-			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
-			return err
-		}
-		timepkg.Sleep(100 * timepkg.Millisecond)
-	}
-
-}
-
 func (s *RetryLayerThreadStore) DeleteMembershipForUser(userId string, postID string) error {
 
 	tries := 0
@@ -10918,84 +10897,21 @@ func (s *RetryLayerThreadStore) PermanentDeleteBatchThreadMembershipsForRetentio
 
 }
 
-func (s *RetryLayerThreadStore) Save(thread *model.Thread) (*model.Thread, error) {
+func (s *RetryLayerThreadStore) UpdateLastViewedByThreadIds(userId string, threadIds []string, timestamp int64) error {
 
 	tries := 0
 	for {
-		result, err := s.ThreadStore.Save(thread)
+		err := s.ThreadStore.UpdateLastViewedByThreadIds(userId, threadIds, timestamp)
 		if err == nil {
-			return result, nil
+			return nil
 		}
 		if !isRepeatableError(err) {
-			return result, err
+			return err
 		}
 		tries++
 		if tries >= 3 {
 			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
-			return result, err
-		}
-		timepkg.Sleep(100 * timepkg.Millisecond)
-	}
-
-}
-
-func (s *RetryLayerThreadStore) SaveMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error) {
-
-	tries := 0
-	for {
-		result, err := s.ThreadStore.SaveMembership(membership)
-		if err == nil {
-			return result, nil
-		}
-		if !isRepeatableError(err) {
-			return result, err
-		}
-		tries++
-		if tries >= 3 {
-			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
-			return result, err
-		}
-		timepkg.Sleep(100 * timepkg.Millisecond)
-	}
-
-}
-
-func (s *RetryLayerThreadStore) SaveMultiple(thread []*model.Thread) ([]*model.Thread, int, error) {
-
-	tries := 0
-	for {
-		result, resultVar1, err := s.ThreadStore.SaveMultiple(thread)
-		if err == nil {
-			return result, resultVar1, nil
-		}
-		if !isRepeatableError(err) {
-			return result, resultVar1, err
-		}
-		tries++
-		if tries >= 3 {
-			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
-			return result, resultVar1, err
-		}
-		timepkg.Sleep(100 * timepkg.Millisecond)
-	}
-
-}
-
-func (s *RetryLayerThreadStore) Update(thread *model.Thread) (*model.Thread, error) {
-
-	tries := 0
-	for {
-		result, err := s.ThreadStore.Update(thread)
-		if err == nil {
-			return result, nil
-		}
-		if !isRepeatableError(err) {
-			return result, err
-		}
-		tries++
-		if tries >= 3 {
-			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
-			return result, err
+			return err
 		}
 		timepkg.Sleep(100 * timepkg.Millisecond)
 	}
@@ -11023,27 +10939,6 @@ func (s *RetryLayerThreadStore) UpdateMembership(membership *model.ThreadMembers
 
 }
 
-func (s *RetryLayerThreadStore) UpdateUnreadsByChannel(userId string, changedThreads []string, timestamp int64, updateViewedTimestamp bool) error {
-
-	tries := 0
-	for {
-		err := s.ThreadStore.UpdateUnreadsByChannel(userId, changedThreads, timestamp, updateViewedTimestamp)
-		if err == nil {
-			return nil
-		}
-		if !isRepeatableError(err) {
-			return err
-		}
-		tries++
-		if tries >= 3 {
-			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
-			return err
-		}
-		timepkg.Sleep(100 * timepkg.Millisecond)
-	}
-
-}
-
 func (s *RetryLayerTokenStore) Cleanup(expiryTime int64) {
 
 	s.TokenStore.Cleanup(expiryTime)
diff --git a/store/sqlstore/channel_store.go b/store/sqlstore/channel_store.go
index 675c4f590d..5108c5e67a 100644
--- a/store/sqlstore/channel_store.go
+++ b/store/sqlstore/channel_store.go
@@ -2380,7 +2380,7 @@ func (s SqlChannelStore) UpdateLastViewedAt(channelIds []string, userId string,
 			times[t.Id] = t.LastPostAt
 		}
 		if updateThreads {
-			s.Thread().UpdateUnreadsByChannel(userId, threadsToUpdate, now, true)
+			s.Thread().UpdateLastViewedByThreadIds(userId, threadsToUpdate, now)
 		}
 		return times, nil
 	}
@@ -2425,7 +2425,7 @@ func (s SqlChannelStore) UpdateLastViewedAt(channelIds []string, userId string,
 	}
 
 	if updateThreads {
-		s.Thread().UpdateUnreadsByChannel(userId, threadsToUpdate, now, true)
+		s.Thread().UpdateLastViewedByThreadIds(userId, threadsToUpdate, now)
 	}
 	return times, nil
 }
@@ -2478,16 +2478,8 @@ func (s SqlChannelStore) CountPostsAfter(channelId string, timestamp int64, user
 // UpdateLastViewedAtPost updates a ChannelMember as if the user last read the channel at the time of the given post.
 // If the provided mentionCount is -1, the given post and all posts after it are considered to be mentions. Returns
 // an updated model.ChannelUnreadAt that can be returned to the client.
-func (s SqlChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount, mentionCountRoot int, updateThreads bool, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
-	var threadsToUpdate []string
+func (s SqlChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount, mentionCountRoot int, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
 	unreadDate := unreadPost.CreateAt - 1
-	if updateThreads {
-		var err error
-		threadsToUpdate, err = s.Thread().CollectThreadsWithNewerReplies(userID, []string{unreadPost.ChannelId}, unreadDate)
-		if err != nil {
-			return nil, err
-		}
-	}
 
 	unread, unreadRoot, err := s.CountPostsAfter(unreadPost.ChannelId, unreadDate, "")
 	if err != nil {
@@ -2554,22 +2546,11 @@ func (s SqlChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID s
 		return nil, errors.Wrapf(err, "failed to get ChannelMember with channelId=%s", unreadPost.ChannelId)
 	}
 
-	if updateThreads {
-		s.Thread().UpdateUnreadsByChannel(userID, threadsToUpdate, unreadDate, false)
-	}
 	return result, nil
 }
 
-func (s SqlChannelStore) IncrementMentionCount(channelId string, userId string, updateThreads, isRoot bool) error {
+func (s SqlChannelStore) IncrementMentionCount(channelId string, userId string, isRoot bool) error {
 	now := model.GetMillis()
-	var threadsToUpdate []string
-	if updateThreads {
-		var err error
-		threadsToUpdate, err = s.Thread().CollectThreadsWithNewerReplies(userId, []string{channelId}, now)
-		if err != nil {
-			return err
-		}
-	}
 	rootInc := 0
 	if isRoot {
 		rootInc = 1
@@ -2587,9 +2568,6 @@ func (s SqlChannelStore) IncrementMentionCount(channelId string, userId string,
 	if err != nil {
 		return errors.Wrapf(err, "failed to Update ChannelMembers with channelId=%s and userId=%s", channelId, userId)
 	}
-	if updateThreads {
-		s.Thread().UpdateUnreadsByChannel(userId, threadsToUpdate, now, false)
-	}
 	return nil
 }
 
diff --git a/store/sqlstore/thread_store.go b/store/sqlstore/thread_store.go
index 8186da3477..cd64da9b11 100644
--- a/store/sqlstore/thread_store.go
+++ b/store/sqlstore/thread_store.go
@@ -6,7 +6,6 @@ package sqlstore
 import (
 	"context"
 	"database/sql"
-	"encoding/json"
 	"strconv"
 	"sync"
 	"time"
@@ -32,70 +31,6 @@ func newSqlThreadStore(sqlStore *SqlStore) store.ThreadStore {
 	}
 }
 
-func threadSliceColumns() []string {
-	return []string{"PostId", "ChannelId", "LastReplyAt", "ReplyCount", "Participants"}
-}
-
-func threadToSlice(thread *model.Thread) []interface{} {
-	return []interface{}{
-		thread.PostId,
-		thread.ChannelId,
-		thread.LastReplyAt,
-		thread.ReplyCount,
-		model.ArrayToJSON(thread.Participants),
-	}
-}
-
-func (s *SqlThreadStore) SaveMultiple(threads []*model.Thread) ([]*model.Thread, int, error) {
-	builder := s.getQueryBuilder().
-		Insert("Threads").
-		Columns(threadSliceColumns()...)
-	for _, thread := range threads {
-		builder = builder.Values(threadToSlice(thread)...)
-	}
-	query, args, err := builder.ToSql()
-	if err != nil {
-		return nil, -1, errors.Wrap(err, "thread_tosql")
-	}
-
-	if _, err := s.GetMasterX().Exec(query, args...); err != nil {
-		return nil, -1, errors.Wrap(err, "failed to save Post")
-	}
-
-	return threads, -1, nil
-}
-
-func (s *SqlThreadStore) Save(thread *model.Thread) (*model.Thread, error) {
-	threads, _, err := s.SaveMultiple([]*model.Thread{thread})
-	if err != nil {
-		return nil, err
-	}
-	return threads[0], nil
-}
-
-func (s *SqlThreadStore) Update(thread *model.Thread) (*model.Thread, error) {
-	jsonParticipants, err := json.Marshal(thread.Participants)
-	if err != nil {
-		return nil, errors.Wrap(err, "failed marshaling thread participants")
-	}
-	query, args, err := s.getQueryBuilder().
-		Update("Threads").
-		Set("ChannelId", thread.ChannelId).
-		Set("ReplyCount", thread.ReplyCount).
-		Set("LastReplyAt", thread.LastReplyAt).
-		Set("Participants", string(jsonParticipants)).
-		Where(sq.Eq{"PostId": thread.PostId}).
-		ToSql()
-	if err != nil {
-		return nil, errors.Wrap(err, "thread_tosql")
-	}
-	if _, err := s.GetMasterX().Exec(query, args...); err != nil {
-		return nil, errors.Wrapf(err, "failed to update thread with id=%s", thread.PostId)
-	}
-
-	return thread, nil
-}
-
 func (s *SqlThreadStore) Get(id string) (*model.Thread, error) {
 	var thread model.Thread
 	query, args, err := s.getQueryBuilder().
@@ -575,6 +510,9 @@ func (s *SqlThreadStore) GetThreadForUser(teamId string, threadMembership *model
 
 	return result, nil
 }
+
+// MarkAllAsReadInChannels marks all threads for the given user in the given channels as read from
+// the current time.
 func (s *SqlThreadStore) MarkAllAsReadInChannels(userID string, channelIDs []string) error {
 	threadIDs := []string{}
 
@@ -599,6 +537,7 @@ func (s *SqlThreadStore) MarkAllAsReadInChannels(userID string, channelIDs []str
 		Where(sq.Eq{"UserId": userID}).
 		Set("LastViewed", timestamp).
 		Set("UnreadMentions", 0).
+		Set("LastUpdated", model.GetMillis()).
 		ToSql()
 	if _, err := s.GetMasterX().Exec(query, args...); err != nil {
 		return errors.Wrapf(err, "failed to update thread read state for user id=%s", userID)
@@ -606,6 +545,9 @@ func (s *SqlThreadStore) MarkAllAsReadInChannels(userID string, channelIDs []str
 	return nil
 
 }
+
+// MarkAllAsRead marks all threads for the given user in the given team as read from the current
+// time.
 func (s *SqlThreadStore) MarkAllAsRead(userId, teamId string) error {
 	memberships, err := s.GetMembershipsForUser(userId, teamId)
 	if err != nil {
@@ -622,6 +564,7 @@ func (s *SqlThreadStore) MarkAllAsRead(userId, teamId string) error {
 		Where(sq.Eq{"UserId": userId}).
 		Set("LastViewed", timestamp).
 		Set("UnreadMentions", 0).
+		Set("LastUpdated", model.GetMillis()).
 		ToSql()
 	if _, err := s.GetMasterX().Exec(query, args...); err != nil {
 		return errors.Wrapf(err, "failed to update thread read state for user id=%s", userId)
@@ -629,12 +572,14 @@ func (s *SqlThreadStore) MarkAllAsRead(userId, teamId string) error {
 	return nil
 }
 
+// MarkAsRead marks the given thread for the given user as unread from the given timestamp.
 func (s *SqlThreadStore) MarkAsRead(userId, threadId string, timestamp int64) error {
 	query, args, _ := s.getQueryBuilder().
 		Update("ThreadMemberships").
 		Where(sq.Eq{"UserId": userId}).
 		Where(sq.Eq{"PostId": threadId}).
 		Set("LastViewed", timestamp).
+		Set("LastUpdated", model.GetMillis()).
 		ToSql()
 	if _, err := s.GetMasterX().Exec(query, args...); err != nil {
 		return errors.Wrapf(err, "failed to update thread read state for user id=%s thread_id=%v", userId, threadId)
@@ -642,19 +587,6 @@ func (s *SqlThreadStore) MarkAsRead(userId, threadId string, timestamp int64) er
 	return nil
 }
 
-func (s *SqlThreadStore) Delete(threadId string) error {
-	query, args, _ := s.getQueryBuilder().Delete("Threads").Where(sq.Eq{"PostId": threadId}).ToSql()
-	if _, err := s.GetMasterX().Exec(query, args...); err != nil {
-		return errors.Wrap(err, "failed to update threads")
-	}
-
-	return nil
-}
-
-func (s *SqlThreadStore) SaveMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error) {
-	return s.saveMembership(s.GetMasterX(), membership)
-}
-
 func (s *SqlThreadStore) saveMembership(ex sqlxExecutor, membership *model.ThreadMembership) (*model.ThreadMembership, error) {
 	query, args, err := s.getQueryBuilder().
 		Insert("ThreadMemberships").
@@ -875,19 +807,20 @@ func (s *SqlThreadStore) CollectThreadsWithNewerReplies(userId string, channelId
 	return changedThreads, nil
 }
 
-func (s *SqlThreadStore) UpdateUnreadsByChannel(userId string, changedThreads []string, timestamp int64, updateViewedTimestamp bool) error {
-	if len(changedThreads) == 0 {
+// UpdateLastViewedByThreadIds marks the given threads as read up to the given timestamp. If there
+// are no newer posts, it effectively marks the thread as read. If there are newer posts, say
+// because the user explicitly marked a past post as unread, the thread will be considered unread
+// past the given timestamp.
+func (s *SqlThreadStore) UpdateLastViewedByThreadIds(userId string, threadIds []string, timestamp int64) error {
+	if len(threadIds) == 0 {
 		return nil
 	}
 
 	qb := s.getQueryBuilder().
 		Update("ThreadMemberships").
-		Where(sq.Eq{"UserId": userId, "PostId": changedThreads}).
-		Set("LastUpdated", timestamp)
-
-	if updateViewedTimestamp {
-		qb = qb.Set("LastViewed", timestamp)
-	}
+		Where(sq.Eq{"UserId": userId, "PostId": threadIds}).
+		Set("LastViewed", timestamp).
+		Set("LastUpdated", model.GetMillis())
 	updateQuery, updateArgs, _ := qb.ToSql()
 
 	if _, err := s.GetMasterX().Exec(updateQuery, updateArgs...); err != nil {
diff --git a/store/store.go b/store/store.go
index ec26fa24bf..358f7ecae2 100644
--- a/store/store.go
+++ b/store/store.go
@@ -224,9 +224,9 @@ type ChannelStore interface {
 	PermanentDeleteMembersByUser(userID string) error
 	PermanentDeleteMembersByChannel(channelID string) error
 	UpdateLastViewedAt(channelIds []string, userID string, updateThreads bool) (map[string]int64, error)
-	UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount, mentionCountRoot int, updateThreads bool, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error)
+	UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount, mentionCountRoot int, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error)
 	CountPostsAfter(channelID string, timestamp int64, userID string) (int, int, error)
-	IncrementMentionCount(channelID string, userID string, updateThreads, isRoot bool) error
+	IncrementMentionCount(channelID string, userID string, isRoot bool) error
 	AnalyticsTypeCount(teamID string, channelType model.ChannelType) (int64, error)
 	GetMembersForUser(teamID string, userID string) (model.ChannelMembers, error)
 	GetTeamMembersForChannel(channelID string) ([]string, error)
@@ -292,28 +292,23 @@ type ChannelMemberHistoryStore interface {
 type ThreadStore interface {
 	GetThreadFollowers(threadID string, fetchOnlyActive bool) ([]string, error)
 
-	SaveMultiple(thread []*model.Thread) ([]*model.Thread, int, error)
-	Save(thread *model.Thread) (*model.Thread, error)
-	Update(thread *model.Thread) (*model.Thread, error)
 	Get(id string) (*model.Thread, error)
 	GetThreadsForUser(userId, teamID string, opts model.GetUserThreadsOpts) (*model.Threads, error)
 	GetThreadForUser(teamID string, threadMembership *model.ThreadMembership, extended bool) (*model.ThreadResponse, error)
 	GetTeamsUnreadForUser(userID string, teamIDs []string) (map[string]*model.TeamUnread, error)
-	Delete(postID string) error
 	GetPosts(threadID string, since int64) ([]*model.Post, error)
 
 	MarkAllAsRead(userID, teamID string) error
 	MarkAllAsReadInChannels(userID string, channelIDs []string) error
 	MarkAsRead(userID, threadID string, timestamp int64) error
 
-	SaveMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error)
 	UpdateMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error)
 	GetMembershipsForUser(userId, teamID string) ([]*model.ThreadMembership, error)
 	GetMembershipForUser(userId, postID string) (*model.ThreadMembership, error)
 	DeleteMembershipForUser(userId, postID string) error
 	MaintainMembership(userID, postID string, opts ThreadMembershipOpts) (*model.ThreadMembership, error)
 	CollectThreadsWithNewerReplies(userId string, channelIds []string, timestamp int64) ([]string, error)
-	UpdateUnreadsByChannel(userId string, changedThreads []string, timestamp int64, updateViewedTimestamp bool) error
+	UpdateLastViewedByThreadIds(userId string, threadIds []string, timestamp int64) error
 	PermanentDeleteBatchForRetentionPolicies(now, globalPolicyEndTime, limit int64, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error)
 	PermanentDeleteBatchThreadMembershipsForRetentionPolicies(now, globalPolicyEndTime, limit int64, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error)
 	DeleteOrphanedRows(limit int) (deleted int64, err error)
diff --git a/store/storetest/channel_store.go b/store/storetest/channel_store.go
index cac7085140..74ffaa6c19 100644
--- a/store/storetest/channel_store.go
+++ b/store/storetest/channel_store.go
@@ -4790,16 +4790,16 @@ func testChannelStoreIncrementMentionCount(t *testing.T, ss store.Store) {
 	_, err := ss.Channel().SaveMember(&m1)
 	require.NoError(t, err)
 
-	err = ss.Channel().IncrementMentionCount(m1.ChannelId, m1.UserId, false, false)
+	err = ss.Channel().IncrementMentionCount(m1.ChannelId, m1.UserId, false)
 	require.NoError(t, err, "failed to update")
 
-	err = ss.Channel().IncrementMentionCount(m1.ChannelId, "missing id", false, false)
+	err = ss.Channel().IncrementMentionCount(m1.ChannelId, "missing id", false)
 	require.NoError(t, err, "failed to update")
 
-	err = ss.Channel().IncrementMentionCount("missing id", m1.UserId, false, false)
+	err = ss.Channel().IncrementMentionCount("missing id", m1.UserId, false)
 	require.NoError(t, err, "failed to update")
 
-	err = ss.Channel().IncrementMentionCount("missing id", "missing id", false, false)
+	err = ss.Channel().IncrementMentionCount("missing id", "missing id", false)
 	require.NoError(t, err, "failed to update")
 }
 
diff --git a/store/storetest/mocks/ChannelStore.go b/store/storetest/mocks/ChannelStore.go
index 4071b1a049..a1b4b4471a 100644
--- a/store/storetest/mocks/ChannelStore.go
+++ b/store/storetest/mocks/ChannelStore.go
@@ -1508,13 +1508,13 @@ func (_m *ChannelStore) GroupSyncedChannelCount() (int64, error) {
 	return r0, r1
 }
 
-// IncrementMentionCount provides a mock function with given fields: channelID, userID, updateThreads, isRoot
-func (_m *ChannelStore) IncrementMentionCount(channelID string, userID string, updateThreads bool, isRoot bool) error {
-	ret := _m.Called(channelID, userID, updateThreads, isRoot)
+// IncrementMentionCount provides a mock function with given fields: channelID, userID, isRoot
+func (_m *ChannelStore) IncrementMentionCount(channelID string, userID string, isRoot bool) error {
+	ret := _m.Called(channelID, userID, isRoot)
 
 	var r0 error
-	if rf, ok := ret.Get(0).(func(string, string, bool, bool) error); ok {
-		r0 = rf(channelID, userID, updateThreads, isRoot)
+	if rf, ok := ret.Get(0).(func(string, string, bool) error); ok {
+		r0 = rf(channelID, userID, isRoot)
 	} else {
 		r0 = ret.Error(0)
 	}
@@ -2031,13 +2031,13 @@ func (_m *ChannelStore) UpdateLastViewedAt(channelIds []string, userID string, u
 	return r0, r1
 }
 
-// UpdateLastViewedAtPost provides a mock function with given fields: unreadPost, userID, mentionCount, mentionCountRoot, updateThreads, setUnreadCountRoot
-func (_m *ChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount int, mentionCountRoot int, updateThreads bool, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
-	ret := _m.Called(unreadPost, userID, mentionCount, mentionCountRoot, updateThreads, setUnreadCountRoot)
+// UpdateLastViewedAtPost provides a mock function with given fields: unreadPost, userID, mentionCount, mentionCountRoot, setUnreadCountRoot
+func (_m *ChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount int, mentionCountRoot int, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
+	ret := _m.Called(unreadPost, userID, mentionCount, mentionCountRoot, setUnreadCountRoot)
 
 	var r0 *model.ChannelUnreadAt
-	if rf, ok := ret.Get(0).(func(*model.Post, string, int, int, bool, bool) *model.ChannelUnreadAt); ok {
-		r0 = rf(unreadPost, userID, mentionCount, mentionCountRoot, updateThreads, setUnreadCountRoot)
+	if rf, ok := ret.Get(0).(func(*model.Post, string, int, int, bool) *model.ChannelUnreadAt); ok {
+		r0 = rf(unreadPost, userID, mentionCount, mentionCountRoot, setUnreadCountRoot)
 	} else {
 		if ret.Get(0) != nil {
 			r0 = ret.Get(0).(*model.ChannelUnreadAt)
@@ -2045,8 +2045,8 @@ func (_m *ChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID st
 	}
 
 	var r1 error
-	if rf, ok := ret.Get(1).(func(*model.Post, string, int, int, bool, bool) error); ok {
-		r1 = rf(unreadPost, userID, mentionCount, mentionCountRoot, updateThreads, setUnreadCountRoot)
+	if rf, ok := ret.Get(1).(func(*model.Post, string, int, int, bool) error); ok {
+		r1 = rf(unreadPost, userID, mentionCount, mentionCountRoot, setUnreadCountRoot)
 	} else {
 		r1 = ret.Error(1)
 	}
diff --git a/store/storetest/mocks/ThreadStore.go b/store/storetest/mocks/ThreadStore.go
index fbe2bc4251..2321d02212 100644
--- a/store/storetest/mocks/ThreadStore.go
+++ b/store/storetest/mocks/ThreadStore.go
@@ -38,20 +38,6 @@ func (_m *ThreadStore) CollectThreadsWithNewerReplies(userId string, channelIds
 	return r0, r1
 }
 
-// Delete provides a mock function with given fields: postID
-func (_m *ThreadStore) Delete(postID string) error {
-	ret := _m.Called(postID)
-
-	var r0 error
-	if rf, ok := ret.Get(0).(func(string) error); ok {
-		r0 = rf(postID)
-	} else {
-		r0 = ret.Error(0)
-	}
-
-	return r0
-}
-
 // DeleteMembershipForUser provides a mock function with given fields: userId, postID
 func (_m *ThreadStore) DeleteMembershipForUser(userId string, postID string) error {
 	ret := _m.Called(userId, postID)
@@ -413,103 +399,18 @@ func (_m *ThreadStore) PermanentDeleteBatchThreadMembershipsForRetentionPolicies
 	return r0, r1, r2
 }
 
-// Save provides a mock function with given fields: thread
-func (_m *ThreadStore) Save(thread *model.Thread) (*model.Thread, error) {
-	ret := _m.Called(thread)
+// UpdateLastViewedByThreadIds provides a mock function with given fields: userId, threadIds, timestamp
+func (_m *ThreadStore) UpdateLastViewedByThreadIds(userId string, threadIds []string, timestamp int64) error {
+	ret := _m.Called(userId, threadIds, timestamp)
 
-	var r0 *model.Thread
-	if rf, ok := ret.Get(0).(func(*model.Thread) *model.Thread); ok {
-		r0 = rf(thread)
+	var r0 error
+	if rf, ok := ret.Get(0).(func(string, []string, int64) error); ok {
+		r0 = rf(userId, threadIds, timestamp)
 	} else {
-		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(*model.Thread)
-		}
+		r0 = ret.Error(0)
 	}
 
-	var r1 error
-	if rf, ok := ret.Get(1).(func(*model.Thread) error); ok {
-		r1 = rf(thread)
-	} else {
-		r1 = ret.Error(1)
-	}
-
-	return r0, r1
-}
-
-// SaveMembership provides a mock function with given fields: membership
-func (_m *ThreadStore) SaveMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error) {
-	ret := _m.Called(membership)
-
-	var r0 *model.ThreadMembership
-	if rf, ok := ret.Get(0).(func(*model.ThreadMembership) *model.ThreadMembership); ok {
-		r0 = rf(membership)
-	} else {
-		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(*model.ThreadMembership)
-		}
-	}
-
-	var r1 error
-	if rf, ok := ret.Get(1).(func(*model.ThreadMembership) error); ok {
-		r1 = rf(membership)
-	} else {
-		r1 = ret.Error(1)
-	}
-
-	return r0, r1
-}
-
-// SaveMultiple provides a mock function with given fields: thread
-func (_m *ThreadStore) SaveMultiple(thread []*model.Thread) ([]*model.Thread, int, error) {
-	ret := _m.Called(thread)
-
-	var r0 []*model.Thread
-	if rf, ok := ret.Get(0).(func([]*model.Thread) []*model.Thread); ok {
-		r0 = rf(thread)
-	} else {
-		if ret.Get(0) != nil {
-			r0 = ret.Get(0).([]*model.Thread)
-		}
-	}
-
-	var r1 int
-	if rf, ok := ret.Get(1).(func([]*model.Thread) int); ok {
-		r1 = rf(thread)
-	} else {
-		r1 = ret.Get(1).(int)
-	}
-
-	var r2 error
-	if rf, ok := ret.Get(2).(func([]*model.Thread) error); ok {
-		r2 = rf(thread)
-	} else {
-		r2 = ret.Error(2)
-	}
-
-	return r0, r1, r2
-}
-
-// Update provides a mock function with given fields: thread
-func (_m *ThreadStore) Update(thread *model.Thread) (*model.Thread, error) {
-	ret := _m.Called(thread)
-
-	var r0 *model.Thread
-	if rf, ok := ret.Get(0).(func(*model.Thread) *model.Thread); ok {
-		r0 = rf(thread)
-	} else {
-		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(*model.Thread)
-		}
-	}
-
-	var r1 error
-	if rf, ok := ret.Get(1).(func(*model.Thread) error); ok {
-		r1 = rf(thread)
-	} else {
-		r1 = ret.Error(1)
-	}
-
-	return r0, r1
+	return r0
 }
 
 // UpdateMembership provides a mock function with given fields: membership
@@ -534,17 +435,3 @@ func (_m *ThreadStore) UpdateMembership(membership *model.ThreadMembership) (*mo
 
 	return r0, r1
 }
-
-// UpdateUnreadsByChannel provides a mock function with given fields: userId, changedThreads, timestamp, updateViewedTimestamp
-func (_m *ThreadStore) UpdateUnreadsByChannel(userId string, changedThreads []string, timestamp int64, updateViewedTimestamp bool) error {
-	ret := _m.Called(userId, changedThreads, timestamp, updateViewedTimestamp)
-
-	var r0 error
-	if rf, ok := ret.Get(0).(func(string, []string, int64, bool) error); ok {
-		r0 = rf(userId, changedThreads, timestamp, updateViewedTimestamp)
-	} else {
-		r0 = ret.Error(0)
-	}
-
-	return r0
-}
diff --git a/store/storetest/post_store.go b/store/storetest/post_store.go
index bb2f32e4fc..45ddc55f9d 100644
--- a/store/storetest/post_store.go
+++ b/store/storetest/post_store.go
@@ -510,15 +510,10 @@ func testPostStoreGetForThread(t *testing.T, ss store.Store) {
 		_, err = ss.Post().Save(&model.Post{ChannelId: o1.ChannelId, UserId: model.NewId(), Message: NewTestId(), RootId: o1.Id})
 		require.NoError(t, err)
 
-		threadMembership := &model.ThreadMembership{
-			PostId:         o1.Id,
-			UserId:         o1.UserId,
-			Following:      true,
-			LastViewed:     0,
-			LastUpdated:    0,
-			UnreadMentions: 0,
-		}
-		_, err = ss.Thread().SaveMembership(threadMembership)
+		_, err = ss.Thread().MaintainMembership(o1.UserId, o1.Id, store.ThreadMembershipOpts{
+			Following:       true,
+			UpdateFollowing: true,
+		})
 		require.NoError(t, err)
 		r1, err := ss.Post().Get(context.Background(), o1.Id, false, true, false, o1.UserId)
 		require.NoError(t, err)
@@ -533,15 +528,10 @@ func testPostStoreGetForThread(t *testing.T, ss store.Store) {
 		_, err = ss.Post().Save(&model.Post{ChannelId: o1.ChannelId, UserId: model.NewId(), Message: NewTestId(), RootId: o1.Id})
 		require.NoError(t, err)
 
-		threadMembership := &model.ThreadMembership{
-			PostId:         o1.Id,
-			UserId:         o1.UserId,
-			Following:      false,
-			LastViewed:     0,
-			LastUpdated:    0,
-			UnreadMentions: 0,
-		}
-		_, err = ss.Thread().SaveMembership(threadMembership)
+		_, err = ss.Thread().MaintainMembership(o1.UserId, o1.Id, store.ThreadMembershipOpts{
+			Following:       false,
+			UpdateFollowing: true,
+		})
 		require.NoError(t, err)
 		r1, err := ss.Post().Get(context.Background(), o1.Id, false, true, false, o1.UserId)
 		require.NoError(t, err)
diff --git a/store/storetest/thread_store.go b/store/storetest/thread_store.go
index 46a1829bf7..7a863e97de 100644
--- a/store/storetest/thread_store.go
+++ b/store/storetest/thread_store.go
@@ -16,13 +16,12 @@ import (
 )
 
 func TestThreadStore(t *testing.T, ss store.Store, s SqlStore) {
-	t.Run("ThreadSQLOperations", func(t *testing.T) { testThreadSQLOperations(t, ss, s) })
 	t.Run("ThreadStorePopulation", func(t *testing.T) { testThreadStorePopulation(t, ss) })
 	t.Run("ThreadStorePermanentDeleteBatchForRetentionPolicies", func(t *testing.T) {
 		testThreadStorePermanentDeleteBatchForRetentionPolicies(t, ss)
 	})
 	t.Run("ThreadStorePermanentDeleteBatchThreadMembershipsForRetentionPolicies", func(t *testing.T) {
-		testThreadStorePermanentDeleteBatchThreadMembershipsForRetentionPolicies(t, ss)
+		testThreadStorePermanentDeleteBatchThreadMembershipsForRetentionPolicies(t, ss, s)
 	})
 	t.Run("GetTeamsUnreadForUser", func(t *testing.T) { testGetTeamsUnreadForUser(t, ss) })
 }
@@ -263,61 +262,6 @@ func testThreadStorePopulation(t *testing.T, ss store.Store) {
 		require.Nil(t, thread2)
 	})
 
-	t.Run("Thread last updated is changed when channel is updated after UpdateLastViewedAtPost", func(t *testing.T) {
-		newPosts := makeSomePosts()
-		opts := store.ThreadMembershipOpts{
-			Following:             true,
-			IncrementMentions:     false,
-			UpdateFollowing:       true,
-			UpdateViewedTimestamp: false,
-			UpdateParticipants:    false,
-		}
-		_, e := ss.Thread().MaintainMembership(newPosts[0].UserId, newPosts[0].Id, opts)
-		require.NoError(t, e)
-		m, err1 := ss.Thread().GetMembershipForUser(newPosts[0].UserId, newPosts[0].Id)
-		require.NoError(t, err1)
-		m.LastUpdated -= 1000
-		_, err := ss.Thread().UpdateMembership(m)
-		require.NoError(t, err)
-
-		_, err = ss.Channel().UpdateLastViewedAtPost(newPosts[0], newPosts[0].UserId, 0, 0, true, true)
-		require.NoError(t, err)
-
-		assert.Eventually(t, func() bool {
-			m2, err2 := ss.Thread().GetMembershipForUser(newPosts[0].UserId, newPosts[0].Id)
-			require.NoError(t, err2)
-			return m2.LastUpdated > m.LastUpdated
-		}, time.Second, 10*time.Millisecond)
-	})
-
-	t.Run("Thread last updated is changed when channel is updated after IncrementMentionCount", func(t *testing.T) {
-		newPosts := makeSomePosts()
-
-		opts := store.ThreadMembershipOpts{
-			Following:             true,
-			IncrementMentions:     false,
-			UpdateFollowing:       true,
-			UpdateViewedTimestamp: false,
-			UpdateParticipants:    false,
-		}
-		_, e := ss.Thread().MaintainMembership(newPosts[0].UserId, newPosts[0].Id, opts)
-		require.NoError(t, e)
-		m, err1 := ss.Thread().GetMembershipForUser(newPosts[0].UserId, newPosts[0].Id)
-		require.NoError(t, err1)
-		m.LastUpdated -= 1000
-		_, err := ss.Thread().UpdateMembership(m)
-		require.NoError(t, err)
-
-		err = ss.Channel().IncrementMentionCount(newPosts[0].ChannelId, newPosts[0].UserId, true, false)
-		require.NoError(t, err)
-
-		assert.Eventually(t, func() bool {
-			m2, err2 := ss.Thread().GetMembershipForUser(newPosts[0].UserId, newPosts[0].Id)
-			require.NoError(t, err2)
-			return m2.LastUpdated > m.LastUpdated
-		}, time.Second, 10*time.Millisecond)
-	})
-
 	t.Run("Thread last updated is changed when channel is updated after UpdateLastViewedAt", func(t *testing.T) {
 		newPosts := makeSomePosts()
 		opts := store.ThreadMembershipOpts{
@@ -394,33 +338,6 @@ func testThreadStorePopulation(t *testing.T, ss store.Store) {
 		require.NotEqual(t, int64(0), tm.LastViewed)
 	})
 
-	t.Run("Thread last updated is changed when channel is updated after UpdateLastViewedAtPost for mark unread", func(t *testing.T) {
-		newPosts := makeSomePosts()
-		opts := store.ThreadMembershipOpts{
-			Following:             true,
-			IncrementMentions:     false,
-			UpdateFollowing:       true,
-			UpdateViewedTimestamp: false,
-			UpdateParticipants:    false,
-		}
-		_, e := ss.Thread().MaintainMembership(newPosts[0].UserId, newPosts[0].Id, opts)
-		require.NoError(t, e)
-		m, err1 := ss.Thread().GetMembershipForUser(newPosts[0].UserId, newPosts[0].Id)
-		require.NoError(t, err1)
-		m.LastUpdated += 1000
-		_, err := ss.Thread().UpdateMembership(m)
-		require.NoError(t, err)
-
-		_, err = ss.Channel().UpdateLastViewedAtPost(newPosts[0], newPosts[0].UserId, 0, 0, true, true)
-		require.NoError(t, err)
-
-		assert.Eventually(t, func() bool {
-			m2, err2 := ss.Thread().GetMembershipForUser(newPosts[0].UserId, newPosts[0].Id)
-			require.NoError(t, err2)
-			return m2.LastUpdated < m.LastUpdated
-		}, time.Second, 10*time.Millisecond)
-	})
-
 	t.Run("Updating post does not make thread unread", func(t *testing.T) {
 		newPosts := makeSomePosts()
 		opts := store.ThreadMembershipOpts{
@@ -503,24 +420,6 @@ func testThreadStorePopulation(t *testing.T, ss store.Store) {
 	})
 }
 
-func testThreadSQLOperations(t *testing.T, ss store.Store, s SqlStore) {
-	t.Run("Save", func(t *testing.T) {
-		threadToSave := &model.Thread{
-			PostId:       model.NewId(),
-			ChannelId:    model.NewId(),
-			LastReplyAt:  10,
-			ReplyCount:   5,
-			Participants: model.StringArray{model.NewId(), model.NewId()},
-		}
-		_, err := ss.Thread().Save(threadToSave)
-		require.NoError(t, err)
-
-		th, err := ss.Thread().Get(threadToSave.PostId)
-		require.NoError(t, err)
-		require.Equal(t, threadToSave, th)
-	})
-}
-
 func threadStoreCreateReply(t *testing.T, ss store.Store, channelID, postID, userID string, createAt int64) *model.Post {
 	reply, err := ss.Post().Save(&model.Post{
 		ChannelId: channelID,
@@ -607,7 +506,7 @@ func testThreadStorePermanentDeleteBatchForRetentionPolicies(t *testing.T, ss st
 	assert.Nil(t, thread, "thread should have been deleted by team policy")
 }
 
-func testThreadStorePermanentDeleteBatchThreadMembershipsForRetentionPolicies(t *testing.T, ss store.Store) {
+func testThreadStorePermanentDeleteBatchThreadMembershipsForRetentionPolicies(t *testing.T, ss store.Store, s SqlStore) {
 	const limit = 1000
 	userID := model.NewId()
 	createThreadMembership := func(userID, postID string) *model.ThreadMembership {
@@ -695,7 +594,7 @@ func testThreadStorePermanentDeleteBatchThreadMembershipsForRetentionPolicies(t
 	// Delete team policy and thread
 	err = ss.RetentionPolicy().Delete(teamPolicy.ID)
 	require.NoError(t, err)
-	err = ss.Thread().Delete(post.Id)
+	_, err = s.GetMasterX().Exec("DELETE FROM Threads WHERE PostId='" + post.Id + "'")
 	require.NoError(t, err)
 
 	deleted, err := ss.Thread().DeleteOrphanedRows(1000)
diff --git a/store/storetest/user_store.go b/store/storetest/user_store.go
index 4caeb67701..f9079bbe28 100644
--- a/store/storetest/user_store.go
+++ b/store/storetest/user_store.go
@@ -2315,7 +2315,7 @@ func testUserUnreadCount(t *testing.T, ss store.Store) {
 	// Post one message with mention to open channel
 	_, nErr = ss.Post().Save(&p1)
 	require.NoError(t, nErr)
-	nErr = ss.Channel().IncrementMentionCount(c1.Id, u2.Id, false, false)
+	nErr = ss.Channel().IncrementMentionCount(c1.Id, u2.Id, false)
 	require.NoError(t, nErr)
 
 	// Post 2 messages without mention to direct channel
@@ -2326,7 +2326,7 @@ func testUserUnreadCount(t *testing.T, ss store.Store) {
 
 	_, nErr = ss.Post().Save(&p2)
 	require.NoError(t, nErr)
-	nErr = ss.Channel().IncrementMentionCount(c2.Id, u2.Id, false, false)
+	nErr = ss.Channel().IncrementMentionCount(c2.Id, u2.Id, false)
 	require.NoError(t, nErr)
 
 	p3 := model.Post{}
@@ -2336,7 +2336,7 @@ func testUserUnreadCount(t *testing.T, ss store.Store) {
 	_, nErr = ss.Post().Save(&p3)
 	require.NoError(t, nErr)
 
-	nErr = ss.Channel().IncrementMentionCount(c2.Id, u2.Id, false, false)
+	nErr = ss.Channel().IncrementMentionCount(c2.Id, u2.Id, false)
 	require.NoError(t, nErr)
 
 	badge, unreadCountErr := ss.User().GetUnreadCount(u2.Id)
diff --git a/store/timerlayer/timerlayer.go b/store/timerlayer/timerlayer.go
index 9950e0ec86..c16d4d03c0 100644
--- a/store/timerlayer/timerlayer.go
+++ b/store/timerlayer/timerlayer.go
@@ -1605,10 +1605,10 @@ func (s *TimerLayerChannelStore) GroupSyncedChannelCount() (int64, error) {
 	return result, err
 }
 
-func (s *TimerLayerChannelStore) IncrementMentionCount(channelID string, userID string, updateThreads bool, isRoot bool) error {
+func (s *TimerLayerChannelStore) IncrementMentionCount(channelID string, userID string, isRoot bool) error {
 	start := timemodule.Now()
 
-	err := s.ChannelStore.IncrementMentionCount(channelID, userID, updateThreads, isRoot)
+	err := s.ChannelStore.IncrementMentionCount(channelID, userID, isRoot)
 
 	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
 	if s.Root.Metrics != nil {
@@ -2126,10 +2126,10 @@ func (s *TimerLayerChannelStore) UpdateLastViewedAt(channelIds []string, userID
 	return result, err
 }
 
-func (s *TimerLayerChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount int, mentionCountRoot int, updateThreads bool, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
+func (s *TimerLayerChannelStore) UpdateLastViewedAtPost(unreadPost *model.Post, userID string, mentionCount int, mentionCountRoot int, setUnreadCountRoot bool) (*model.ChannelUnreadAt, error) {
 	start := timemodule.Now()
 
-	result, err := s.ChannelStore.UpdateLastViewedAtPost(unreadPost, userID, mentionCount, mentionCountRoot, updateThreads, setUnreadCountRoot)
+	result, err := s.ChannelStore.UpdateLastViewedAtPost(unreadPost, userID, mentionCount, mentionCountRoot, setUnreadCountRoot)
 
 	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
 	if s.Root.Metrics != nil {
@@ -8311,22 +8311,6 @@ func (s *TimerLayerThreadStore) CollectThreadsWithNewerReplies(userId string, ch
 	return result, err
 }
 
-func (s *TimerLayerThreadStore) Delete(postID string) error {
-	start := timemodule.Now()
-
-	err := s.ThreadStore.Delete(postID)
-
-	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
-	if s.Root.Metrics != nil {
-		success := "false"
-		if err == nil {
-			success = "true"
-		}
-		s.Root.Metrics.ObserveStoreMethodDuration("ThreadStore.Delete", success, elapsed)
-	}
-	return err
-}
-
 func (s *TimerLayerThreadStore) DeleteMembershipForUser(userId string, postID string) error {
 	start := timemodule.Now()
 
@@ -8599,10 +8583,10 @@ func (s *TimerLayerThreadStore) PermanentDeleteBatchThreadMembershipsForRetentio
 	return result, resultVar1, err
 }
 
-func (s *TimerLayerThreadStore) Save(thread *model.Thread) (*model.Thread, error) {
+func (s *TimerLayerThreadStore) UpdateLastViewedByThreadIds(userId string, threadIds []string, timestamp int64) error {
 	start := timemodule.Now()
 
-	result, err := s.ThreadStore.Save(thread)
+	err := s.ThreadStore.UpdateLastViewedByThreadIds(userId, threadIds, timestamp)
 
 	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
 	if s.Root.Metrics != nil {
@@ -8610,57 +8594,9 @@ func (s *TimerLayerThreadStore) Save(thread *model.Thread) (*model.Thread, error
 		if err == nil {
 			success = "true"
 		}
-		s.Root.Metrics.ObserveStoreMethodDuration("ThreadStore.Save", success, elapsed)
+		s.Root.Metrics.ObserveStoreMethodDuration("ThreadStore.UpdateLastViewedByThreadIds", success, elapsed)
 	}
-	return result, err
-}
-
-func (s *TimerLayerThreadStore) SaveMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error) {
-	start := timemodule.Now()
-
-	result, err := s.ThreadStore.SaveMembership(membership)
-
-	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
-	if s.Root.Metrics != nil {
-		success := "false"
-		if err == nil {
-			success = "true"
-		}
-		s.Root.Metrics.ObserveStoreMethodDuration("ThreadStore.SaveMembership", success, elapsed)
-	}
-	return result, err
-}
-
-func (s *TimerLayerThreadStore) SaveMultiple(thread []*model.Thread) ([]*model.Thread, int, error) {
-	start := timemodule.Now()
-
-	result, resultVar1, err := s.ThreadStore.SaveMultiple(thread)
-
-	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
-	if s.Root.Metrics != nil {
-		success := "false"
-		if err == nil {
-			success = "true"
-		}
-		s.Root.Metrics.ObserveStoreMethodDuration("ThreadStore.SaveMultiple", success, elapsed)
-	}
-	return result, resultVar1, err
-}
-
-func (s *TimerLayerThreadStore) Update(thread *model.Thread) (*model.Thread, error) {
-	start := timemodule.Now()
-
-	result, err := s.ThreadStore.Update(thread)
-
-	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
-	if s.Root.Metrics != nil {
-		success := "false"
-		if err == nil {
-			success = "true"
-		}
-		s.Root.Metrics.ObserveStoreMethodDuration("ThreadStore.Update", success, elapsed)
-	}
-	return result, err
+	return err
 }
 
 func (s *TimerLayerThreadStore) UpdateMembership(membership *model.ThreadMembership) (*model.ThreadMembership, error) {
@@ -8679,22 +8615,6 @@ func (s *TimerLayerThreadStore) UpdateMembership(membership *model.ThreadMembers
 	return result, err
 }
 
-func (s *TimerLayerThreadStore) UpdateUnreadsByChannel(userId string, changedThreads []string, timestamp int64, updateViewedTimestamp bool) error {
-	start := timemodule.Now()
-
-	err := s.ThreadStore.UpdateUnreadsByChannel(userId, changedThreads, timestamp, updateViewedTimestamp)
-
-	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
-	if s.Root.Metrics != nil {
-		success := "false"
-		if err == nil {
-			success = "true"
-		}
-		s.Root.Metrics.ObserveStoreMethodDuration("ThreadStore.UpdateUnreadsByChannel", success, elapsed)
-	}
-	return err
-}
-
 func (s *TimerLayerTokenStore) Cleanup(expiryTime int64) {
 	start := timemodule.Now()