diff --git a/src/TextForEvent.tsx b/src/TextForEvent.tsx
index ef24fb8e48..95341705bf 100644
--- a/src/TextForEvent.tsx
+++ b/src/TextForEvent.tsx
@@ -32,7 +32,7 @@ import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 // any text to display at all. For this reason they return deferred values
 // to avoid the expense of looking up translations when they're not needed.
 
-function textForMemberEvent(ev): () => string | null {
+function textForMemberEvent(ev: MatrixEvent): () => string | null {
     // XXX: SYJS-16 "sender is sometimes null for join messages"
     const senderName = ev.sender ? ev.sender.name : ev.getSender();
     const targetName = ev.target ? ev.target.name : ev.getStateKey();
@@ -127,7 +127,7 @@ function textForMemberEvent(ev): () => string | null {
     }
 }
 
-function textForTopicEvent(ev): () => string | null {
+function textForTopicEvent(ev: MatrixEvent): () => string | null {
     const senderDisplayName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
     return () => _t('%(senderDisplayName)s changed the topic to "%(topic)s".', {
         senderDisplayName,
@@ -135,7 +135,7 @@ function textForTopicEvent(ev): () => string | null {
     });
 }
 
-function textForRoomNameEvent(ev): () => string | null {
+function textForRoomNameEvent(ev: MatrixEvent): () => string | null {
     const senderDisplayName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
 
     if (!ev.getContent().name || ev.getContent().name.trim().length === 0) {
@@ -154,12 +154,12 @@ function textForRoomNameEvent(ev): () => string | null {
     });
 }
 
-function textForTombstoneEvent(ev): () => string | null {
+function textForTombstoneEvent(ev: MatrixEvent): () => string | null {
     const senderDisplayName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
     return () => _t('%(senderDisplayName)s upgraded this room.', { senderDisplayName });
 }
 
-function textForJoinRulesEvent(ev): () => string | null {
+function textForJoinRulesEvent(ev: MatrixEvent): () => string | null {
     const senderDisplayName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
     switch (ev.getContent().join_rule) {
         case "public":
@@ -179,7 +179,7 @@ function textForJoinRulesEvent(ev): () => string | null {
     }
 }
 
-function textForGuestAccessEvent(ev): () => string | null {
+function textForGuestAccessEvent(ev: MatrixEvent): () => string | null {
     const senderDisplayName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
     switch (ev.getContent().guest_access) {
         case "can_join":
@@ -195,7 +195,7 @@ function textForGuestAccessEvent(ev): () => string | null {
     }
 }
 
-function textForRelatedGroupsEvent(ev): () => string | null {
+function textForRelatedGroupsEvent(ev: MatrixEvent): () => string | null {
     const senderDisplayName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
     const groups = ev.getContent().groups || [];
     const prevGroups = ev.getPrevContent().groups || [];
@@ -225,7 +225,7 @@ function textForRelatedGroupsEvent(ev): () => string | null {
     }
 }
 
-function textForServerACLEvent(ev): () => string | null {
+function textForServerACLEvent(ev: MatrixEvent): () => string | null {
     const senderDisplayName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
     const prevContent = ev.getPrevContent();
     const current = ev.getContent();
@@ -255,7 +255,7 @@ function textForServerACLEvent(ev): () => string | null {
     return getText;
 }
 
-function textForMessageEvent(ev): () => string | null {
+function textForMessageEvent(ev: MatrixEvent): () => string | null {
     return () => {
         const senderDisplayName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
         let message = senderDisplayName + ': ' + ev.getContent().body;
@@ -268,7 +268,7 @@ function textForMessageEvent(ev): () => string | null {
     };
 }
 
-function textForCanonicalAliasEvent(ev): () => string | null {
+function textForCanonicalAliasEvent(ev: MatrixEvent): () => string | null {
     const senderName = ev.sender && ev.sender.name ? ev.sender.name : ev.getSender();
     const oldAlias = ev.getPrevContent().alias;
     const oldAltAliases = ev.getPrevContent().alt_aliases || [];
@@ -682,7 +682,7 @@ for (const evType of ALL_RULE_TYPES) {
     stateHandlers[evType] = textForMjolnirEvent;
 }
 
-export function hasText(ev): boolean {
+export function hasText(ev: MatrixEvent): boolean {
     const handler = (ev.isState() ? stateHandlers : handlers)[ev.getType()];
     return Boolean(handler?.(ev));
 }
diff --git a/src/components/structures/RoomView.tsx b/src/components/structures/RoomView.tsx
index a8f9e7ccb6..2fe694a435 100644
--- a/src/components/structures/RoomView.tsx
+++ b/src/components/structures/RoomView.tsx
@@ -917,6 +917,7 @@ export default class RoomView extends React.Component<IProps, IState> {
     // called when state.room is first initialised (either at initial load,
     // after a successful peek, or after we join the room).
     private onRoomLoaded = (room: Room) => {
+        if (this.unmounted) return;
         // Attach a widget store listener only when we get a room
         WidgetLayoutStore.instance.on(WidgetLayoutStore.emissionForRoom(room), this.onWidgetLayoutChange);
         this.onWidgetLayoutChange(); // provoke an update
@@ -931,9 +932,9 @@ export default class RoomView extends React.Component<IProps, IState> {
     };
 
     private async calculateRecommendedVersion(room: Room) {
-        this.setState({
-            upgradeRecommendation: await room.getRecommendedVersion(),
-        });
+        const upgradeRecommendation = await room.getRecommendedVersion();
+        if (this.unmounted) return;
+        this.setState({ upgradeRecommendation });
     }
 
     private async loadMembersIfJoined(room: Room) {
@@ -1023,23 +1024,19 @@ export default class RoomView extends React.Component<IProps, IState> {
     };
 
     private async updateE2EStatus(room: Room) {
-        if (!this.context.isRoomEncrypted(room.roomId)) {
-            return;
-        }
-        if (!this.context.isCryptoEnabled()) {
-            // If crypto is not currently enabled, we aren't tracking devices at all,
-            // so we don't know what the answer is. Let's error on the safe side and show
-            // a warning for this case.
-            this.setState({
-                e2eStatus: E2EStatus.Warning,
-            });
-            return;
+        if (!this.context.isRoomEncrypted(room.roomId)) return;
+
+        // If crypto is not currently enabled, we aren't tracking devices at all,
+        // so we don't know what the answer is. Let's error on the safe side and show
+        // a warning for this case.
+        let e2eStatus = E2EStatus.Warning;
+        if (this.context.isCryptoEnabled()) {
+            /* At this point, the user has encryption on and cross-signing on */
+            e2eStatus = await shieldStatusForRoom(this.context, room);
         }
 
-        /* At this point, the user has encryption on and cross-signing on */
-        this.setState({
-            e2eStatus: await shieldStatusForRoom(this.context, room),
-        });
+        if (this.unmounted) return;
+        this.setState({ e2eStatus });
     }
 
     private onAccountData = (event: MatrixEvent) => {
diff --git a/src/components/structures/TimelinePanel.tsx b/src/components/structures/TimelinePanel.tsx
index 85a048e9b8..c21aac790b 100644
--- a/src/components/structures/TimelinePanel.tsx
+++ b/src/components/structures/TimelinePanel.tsx
@@ -1051,6 +1051,8 @@ class TimelinePanel extends React.Component<IProps, IState> {
             { windowLimit: this.props.timelineCap });
 
         const onLoaded = () => {
+            if (this.unmounted) return;
+
             // clear the timeline min-height when
             // (re)loading the timeline
             if (this.messagePanel.current) {
@@ -1092,6 +1094,8 @@ class TimelinePanel extends React.Component<IProps, IState> {
         };
 
         const onError = (error) => {
+            if (this.unmounted) return;
+
             this.setState({ timelineLoading: false });
             console.error(
                 `Error loading timeline panel at ${eventId}: ${error}`,
diff --git a/src/components/views/messages/SenderProfile.tsx b/src/components/views/messages/SenderProfile.tsx
index bdae9cec4a..d4b74db6d0 100644
--- a/src/components/views/messages/SenderProfile.tsx
+++ b/src/components/views/messages/SenderProfile.tsx
@@ -15,12 +15,14 @@
  */
 
 import React from 'react';
+import { MatrixEvent } from "matrix-js-sdk/src/models/event";
+import { MsgType } from "matrix-js-sdk/src/@types/event";
+
 import Flair from '../elements/Flair';
 import FlairStore from '../../../stores/FlairStore';
 import { getUserNameColorClass } from '../../../utils/FormattingUtils';
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
 import { replaceableComponent } from "../../../utils/replaceableComponent";
-import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 
 interface IProps {
     mxEvent: MatrixEvent;
@@ -36,7 +38,7 @@ interface IState {
 @replaceableComponent("views.messages.SenderProfile")
 export default class SenderProfile extends React.Component<IProps, IState> {
     static contextType = MatrixClientContext;
-    private unmounted: boolean;
+    private unmounted = false;
 
     constructor(props: IProps) {
         super(props);
@@ -49,8 +51,7 @@ export default class SenderProfile extends React.Component<IProps, IState> {
     }
 
     componentDidMount() {
-        this.unmounted = false;
-        this._updateRelatedGroups();
+        this.updateRelatedGroups();
 
         if (this.state.userGroups.length === 0) {
             this.getPublicisedGroups();
@@ -64,35 +65,29 @@ export default class SenderProfile extends React.Component<IProps, IState> {
         this.context.removeListener('RoomState.events', this.onRoomStateEvents);
     }
 
-    async getPublicisedGroups() {
-        if (!this.unmounted) {
-            const userGroups = await FlairStore.getPublicisedGroupsCached(
-                this.context, this.props.mxEvent.getSender(),
-            );
-            this.setState({ userGroups });
-        }
+    private async getPublicisedGroups() {
+        const userGroups = await FlairStore.getPublicisedGroupsCached(this.context, this.props.mxEvent.getSender());
+        if (this.unmounted) return;
+        this.setState({ userGroups });
     }
 
-    onRoomStateEvents = event => {
-        if (event.getType() === 'm.room.related_groups' &&
-            event.getRoomId() === this.props.mxEvent.getRoomId()
-        ) {
-            this._updateRelatedGroups();
+    private onRoomStateEvents = (event: MatrixEvent) => {
+        if (event.getType() === 'm.room.related_groups' && event.getRoomId() === this.props.mxEvent.getRoomId()) {
+            this.updateRelatedGroups();
         }
     };
 
-    _updateRelatedGroups() {
-        if (this.unmounted) return;
+    private updateRelatedGroups() {
         const room = this.context.getRoom(this.props.mxEvent.getRoomId());
         if (!room) return;
 
         const relatedGroupsEvent = room.currentState.getStateEvents('m.room.related_groups', '');
         this.setState({
-            relatedGroups: relatedGroupsEvent ? relatedGroupsEvent.getContent().groups || [] : [],
+            relatedGroups: relatedGroupsEvent?.getContent().groups || [],
         });
     }
 
-    _getDisplayedGroups(userGroups, relatedGroups) {
+    private getDisplayedGroups(userGroups?: string[], relatedGroups?: string[]) {
         let displayedGroups = userGroups || [];
         if (relatedGroups && relatedGroups.length > 0) {
             displayedGroups = relatedGroups.filter((groupId) => {
@@ -113,7 +108,7 @@ export default class SenderProfile extends React.Component<IProps, IState> {
         const displayName = mxEvent.sender?.rawDisplayName || mxEvent.getSender() || "";
         const mxid = mxEvent.sender?.userId || mxEvent.getSender() || "";
 
-        if (msgtype === 'm.emote') {
+        if (msgtype === MsgType.Emote) {
             return null; // emote message must include the name so don't duplicate it
         }
 
@@ -128,7 +123,7 @@ export default class SenderProfile extends React.Component<IProps, IState> {
 
         let flair;
         if (this.props.enableFlair) {
-            const displayedGroups = this._getDisplayedGroups(
+            const displayedGroups = this.getDisplayedGroups(
                 this.state.userGroups, this.state.relatedGroups,
             );
 
diff --git a/src/components/views/rooms/EventTile.tsx b/src/components/views/rooms/EventTile.tsx
index b5a4bc41db..14eab5da2e 100644
--- a/src/components/views/rooms/EventTile.tsx
+++ b/src/components/views/rooms/EventTile.tsx
@@ -1152,11 +1152,11 @@ export default class EventTile extends React.Component<IProps, IState> {
                     "aria-live": ariaLive,
                     "aria-atomic": true,
                     "data-scroll-tokens": scrollToken,
-                }, [
-                    ircTimestamp,
-                    avatar,
-                    sender,
-                    ircPadlock,
+                }, <>
+                    { ircTimestamp }
+                    { avatar }
+                    { sender }
+                    { ircPadlock }
                     <div className="mx_EventTile_reply" key="mx_EventTile_reply">
                         { groupTimestamp }
                         { groupPadlock }
@@ -1169,8 +1169,8 @@ export default class EventTile extends React.Component<IProps, IState> {
                             replacingEventId={this.props.replacingEventId}
                             showUrlPreview={false}
                         />
-                    </div>,
-                ]);
+                    </div>
+                </>);
             }
             default: {
                 const thread = ReplyThread.makeThread(
@@ -1193,10 +1193,10 @@ export default class EventTile extends React.Component<IProps, IState> {
                         "data-scroll-tokens": scrollToken,
                         "onMouseEnter": () => this.setState({ hover: true }),
                         "onMouseLeave": () => this.setState({ hover: false }),
-                    }, [
-                        ircTimestamp,
-                        sender,
-                        ircPadlock,
+                    }, <>
+                        { ircTimestamp }
+                        { sender }
+                        { ircPadlock }
                         <div className="mx_EventTile_line" key="mx_EventTile_line">
                             { groupTimestamp }
                             { groupPadlock }
@@ -1214,11 +1214,10 @@ export default class EventTile extends React.Component<IProps, IState> {
                             { keyRequestInfo }
                             { reactionsRow }
                             { actionBar }
-                        </div>,
-                        msgOption,
-                        avatar,
-
-                    ])
+                        </div>
+                        { msgOption }
+                        { avatar }
+                    </>)
                 );
             }
         }
diff --git a/src/components/views/rooms/LinkPreviewGroup.tsx b/src/components/views/rooms/LinkPreviewGroup.tsx
index 2541b2e375..c9842bdd33 100644
--- a/src/components/views/rooms/LinkPreviewGroup.tsx
+++ b/src/components/views/rooms/LinkPreviewGroup.tsx
@@ -40,10 +40,12 @@ const LinkPreviewGroup: React.FC<IProps> = ({ links, mxEvent, onCancelClick, onH
 
     const ts = mxEvent.getTs();
     const previews = useAsyncMemo<[string, IPreviewUrlResponse][]>(async () => {
-        return Promise.all<[string, IPreviewUrlResponse] | void>(links.map(link => {
-            return cli.getUrlPreview(link, ts).then(preview => [link, preview], error => {
+        return Promise.all<[string, IPreviewUrlResponse] | void>(links.map(async link => {
+            try {
+                return [link, await cli.getUrlPreview(link, ts)];
+            } catch (error) {
                 console.error("Failed to get URL preview: " + error);
-            });
+            }
         })).then(a => a.filter(Boolean)) as Promise<[string, IPreviewUrlResponse][]>;
     }, [links, ts], []);
 
diff --git a/src/components/views/settings/tabs/user/AppearanceUserSettingsTab.tsx b/src/components/views/settings/tabs/user/AppearanceUserSettingsTab.tsx
index 17aa9e5561..a94821e94a 100644
--- a/src/components/views/settings/tabs/user/AppearanceUserSettingsTab.tsx
+++ b/src/components/views/settings/tabs/user/AppearanceUserSettingsTab.tsx
@@ -76,6 +76,7 @@ export default class AppearanceUserSettingsTab extends React.Component<IProps, I
     private readonly MESSAGE_PREVIEW_TEXT = _t("Hey you. You're the best!");
 
     private themeTimer: number;
+    private unmounted = false;
 
     constructor(props: IProps) {
         super(props);
@@ -101,6 +102,7 @@ export default class AppearanceUserSettingsTab extends React.Component<IProps, I
         const client = MatrixClientPeg.get();
         const userId = client.getUserId();
         const profileInfo = await client.getProfileInfo(userId);
+        if (this.unmounted) return;
 
         this.setState({
             userId,
@@ -109,6 +111,10 @@ export default class AppearanceUserSettingsTab extends React.Component<IProps, I
         });
     }
 
+    componentWillUnmount() {
+        this.unmounted = true;
+    }
+
     private calculateThemeState(): IThemeState {
         // We have to mirror the logic from ThemeWatcher.getEffectiveTheme so we
         // show the right values for things.
diff --git a/src/stores/room-list/RoomListStore.ts b/src/stores/room-list/RoomListStore.ts
index a87e45acb7..bedbfebd7f 100644
--- a/src/stores/room-list/RoomListStore.ts
+++ b/src/stores/room-list/RoomListStore.ts
@@ -74,6 +74,7 @@ export class RoomListStoreClass extends AsyncStoreWithClient<IState> {
 
     constructor() {
         super(defaultDispatcher);
+        this.setMaxListeners(20); // CustomRoomTagStore + RoomList + LeftPanel + 8xRoomSubList + spares
     }
 
     private setupWatchers() {