diff --git a/src/DateUtils.ts b/src/DateUtils.ts
index 5973a7c5f2e1..c1aa69aacd6d 100644
--- a/src/DateUtils.ts
+++ b/src/DateUtils.ts
@@ -175,7 +175,7 @@ function withinCurrentYear(prevDate: Date, nextDate: Date): boolean {
     return prevDate.getFullYear() === nextDate.getFullYear();
 }
 
-export function wantsDateSeparator(prevEventDate: Date, nextEventDate: Date): boolean {
+export function wantsDateSeparator(prevEventDate: Date | undefined, nextEventDate: Date | undefined): boolean {
     if (!nextEventDate || !prevEventDate) {
         return false;
     }
diff --git a/src/components/structures/MessagePanel.tsx b/src/components/structures/MessagePanel.tsx
index 98e8f79ec722..2dd432cb9282 100644
--- a/src/components/structures/MessagePanel.tsx
+++ b/src/components/structures/MessagePanel.tsx
@@ -72,7 +72,7 @@ const groupedStateEvents = [
 // check if there is a previous event and it has the same sender as this event
 // and the types are the same/is in continuedTypes and the time between them is <= CONTINUATION_MAX_INTERVAL
 export function shouldFormContinuation(
-    prevEvent: MatrixEvent,
+    prevEvent: MatrixEvent | null,
     mxEvent: MatrixEvent,
     showHiddenEvents: boolean,
     threadsEnabled: boolean,
@@ -821,7 +821,7 @@ export default class MessagePanel extends React.Component<IProps, IState> {
             // here.
             return !this.props.canBackPaginate;
         }
-        return wantsDateSeparator(prevEvent.getDate(), nextEventDate);
+        return wantsDateSeparator(prevEvent.getDate() || undefined, nextEventDate);
     }
 
     // Get a list of read receipts that should be shown next to this event
diff --git a/src/components/views/dialogs/MessageEditHistoryDialog.tsx b/src/components/views/dialogs/MessageEditHistoryDialog.tsx
index 943e7f58d2d6..8775b4eb5c33 100644
--- a/src/components/views/dialogs/MessageEditHistoryDialog.tsx
+++ b/src/components/views/dialogs/MessageEditHistoryDialog.tsx
@@ -130,7 +130,7 @@ export default class MessageEditHistoryDialog extends React.PureComponent<IProps
         }
         const baseEventId = this.props.mxEvent.getId();
         allEvents.forEach((e, i) => {
-            if (!lastEvent || wantsDateSeparator(lastEvent.getDate(), e.getDate())) {
+            if (!lastEvent || wantsDateSeparator(lastEvent.getDate() || undefined, e.getDate() || undefined)) {
                 nodes.push(
                     <li key={e.getTs() + "~"}>
                         <DateSeparator roomId={e.getRoomId()} ts={e.getTs()} />
diff --git a/src/components/views/rooms/SearchResultTile.tsx b/src/components/views/rooms/SearchResultTile.tsx
index 067cbaee3836..3ec68b989f4c 100644
--- a/src/components/views/rooms/SearchResultTile.tsx
+++ b/src/components/views/rooms/SearchResultTile.tsx
@@ -84,7 +84,7 @@ export default class SearchResultTile extends React.Component<IProps> {
                 // is this a continuation of the previous message?
                 const continuation =
                     prevEv &&
-                    !wantsDateSeparator(prevEv.getDate(), mxEv.getDate()) &&
+                    !wantsDateSeparator(prevEv.getDate() || undefined, mxEv.getDate() || undefined) &&
                     shouldFormContinuation(
                         prevEv,
                         mxEv,
@@ -96,7 +96,10 @@ export default class SearchResultTile extends React.Component<IProps> {
                 let lastInSection = true;
                 const nextEv = timeline[j + 1];
                 if (nextEv) {
-                    const willWantDateSeparator = wantsDateSeparator(mxEv.getDate(), nextEv.getDate());
+                    const willWantDateSeparator = wantsDateSeparator(
+                        mxEv.getDate() || undefined,
+                        nextEv.getDate() || undefined,
+                    );
                     lastInSection =
                         willWantDateSeparator ||
                         mxEv.getSender() !== nextEv.getSender() ||
diff --git a/src/utils/exportUtils/HtmlExport.tsx b/src/utils/exportUtils/HtmlExport.tsx
index 6b4240375c6a..8232a15dceb2 100644
--- a/src/utils/exportUtils/HtmlExport.tsx
+++ b/src/utils/exportUtils/HtmlExport.tsx
@@ -1,5 +1,5 @@
 /*
-Copyright 2021 The Matrix.org Foundation C.I.C.
+Copyright 2021, 2023 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -66,7 +66,7 @@ export default class HTMLExporter extends Exporter {
     }
 
     protected async getRoomAvatar(): Promise<ReactNode> {
-        let blob: Blob;
+        let blob: Blob | undefined = undefined;
         const avatarUrl = Avatar.avatarUrlForRoom(this.room, 32, 32, "crop");
         const avatarPath = "room.png";
         if (avatarUrl) {
@@ -85,7 +85,7 @@ export default class HTMLExporter extends Exporter {
                 height={32}
                 name={this.room.name}
                 title={this.room.name}
-                url={blob ? avatarPath : null}
+                url={blob ? avatarPath : ""}
                 resizeMethod="crop"
             />
         );
@@ -96,9 +96,9 @@ export default class HTMLExporter extends Exporter {
         const roomAvatar = await this.getRoomAvatar();
         const exportDate = formatFullDateNoDayNoTime(new Date());
         const creator = this.room.currentState.getStateEvents(EventType.RoomCreate, "")?.getSender();
-        const creatorName = this.room?.getMember(creator)?.rawDisplayName || creator;
-        const exporter = this.client.getUserId();
-        const exporterName = this.room?.getMember(exporter)?.rawDisplayName;
+        const creatorName = (creator ? this.room.getMember(creator)?.rawDisplayName : creator) || creator;
+        const exporter = this.client.getUserId()!;
+        const exporterName = this.room.getMember(exporter)?.rawDisplayName;
         const topic = this.room.currentState.getStateEvents(EventType.RoomTopic, "")?.getContent()?.topic || "";
         const createdText = _t("%(creatorName)s created this room.", {
             creatorName,
@@ -217,20 +217,19 @@ export default class HTMLExporter extends Exporter {
         </html>`;
     }
 
-    protected getAvatarURL(event: MatrixEvent): string {
+    protected getAvatarURL(event: MatrixEvent): string | undefined {
         const member = event.sender;
-        return (
-            member.getMxcAvatarUrl() && mediaFromMxc(member.getMxcAvatarUrl()).getThumbnailOfSourceHttp(30, 30, "crop")
-        );
+        const avatarUrl = member?.getMxcAvatarUrl();
+        return avatarUrl ? mediaFromMxc(avatarUrl).getThumbnailOfSourceHttp(30, 30, "crop") : undefined;
     }
 
     protected async saveAvatarIfNeeded(event: MatrixEvent): Promise<void> {
-        const member = event.sender;
+        const member = event.sender!;
         if (!this.avatars.has(member.userId)) {
             try {
                 const avatarUrl = this.getAvatarURL(event);
                 this.avatars.set(member.userId, true);
-                const image = await fetch(avatarUrl);
+                const image = await fetch(avatarUrl!);
                 const blob = await image.blob();
                 this.addFile(`users/${member.userId.replace(/:/g, "-")}.png`, blob);
             } catch (err) {
@@ -243,15 +242,15 @@ export default class HTMLExporter extends Exporter {
         const ts = event.getTs();
         const dateSeparator = (
             <li key={ts}>
-                <DateSeparator forExport={true} key={ts} roomId={event.getRoomId()} ts={ts} />
+                <DateSeparator forExport={true} key={ts} roomId={event.getRoomId()!} ts={ts} />
             </li>
         );
         return renderToStaticMarkup(dateSeparator);
     }
 
-    protected async needsDateSeparator(event: MatrixEvent, prevEvent: MatrixEvent): Promise<boolean> {
-        if (prevEvent == null) return true;
-        return wantsDateSeparator(prevEvent.getDate(), event.getDate());
+    protected async needsDateSeparator(event: MatrixEvent, prevEvent: MatrixEvent | null): Promise<boolean> {
+        if (!prevEvent) return true;
+        return wantsDateSeparator(prevEvent.getDate() || undefined, event.getDate() || undefined);
     }
 
     public getEventTile(mxEv: MatrixEvent, continuation: boolean): JSX.Element {
@@ -264,9 +263,7 @@ export default class HTMLExporter extends Exporter {
                         isRedacted={mxEv.isRedacted()}
                         replacingEventId={mxEv.replacingEventId()}
                         forExport={true}
-                        readReceipts={null}
                         alwaysShowTimestamps={true}
-                        readReceiptMap={null}
                         showUrlPreview={false}
                         checkUnmounting={() => false}
                         isTwelveHour={false}
@@ -275,7 +272,6 @@ export default class HTMLExporter extends Exporter {
                         permalinkCreator={this.permalinkCreator}
                         lastSuccessful={false}
                         isSelectedEvent={false}
-                        getRelationsForEvent={null}
                         showReactions={false}
                         layout={Layout.Group}
                         showReadReceipts={false}
@@ -286,7 +282,8 @@ export default class HTMLExporter extends Exporter {
     }
 
     protected async getEventTileMarkup(mxEv: MatrixEvent, continuation: boolean, filePath?: string): Promise<string> {
-        const hasAvatar = !!this.getAvatarURL(mxEv);
+        const avatarUrl = this.getAvatarURL(mxEv);
+        const hasAvatar = !!avatarUrl;
         if (hasAvatar) await this.saveAvatarIfNeeded(mxEv);
         const EventTile = this.getEventTile(mxEv, continuation);
         let eventTileMarkup: string;
@@ -312,8 +309,8 @@ export default class HTMLExporter extends Exporter {
         eventTileMarkup = eventTileMarkup.replace(/<span class="mx_MFileBody_info_icon".*?>.*?<\/span>/, "");
         if (hasAvatar) {
             eventTileMarkup = eventTileMarkup.replace(
-                encodeURI(this.getAvatarURL(mxEv)).replace(/&/g, "&amp;"),
-                `users/${mxEv.sender.userId.replace(/:/g, "-")}.png`,
+                encodeURI(avatarUrl).replace(/&/g, "&amp;"),
+                `users/${mxEv.sender!.userId.replace(/:/g, "-")}.png`,
             );
         }
         return eventTileMarkup;
@@ -403,7 +400,7 @@ export default class HTMLExporter extends Exporter {
             if (this.cancelled) return this.cleanUp();
             if (!haveRendererForEvent(event, false)) continue;
 
-            content += this.needsDateSeparator(event, prevEvent) ? this.getDateSeparator(event) : "";
+            content += (await this.needsDateSeparator(event, prevEvent)) ? this.getDateSeparator(event) : "";
             const shouldBeJoined =
                 !this.needsDateSeparator(event, prevEvent) &&
                 shouldFormContinuation(prevEvent, event, false, this.threadsEnabled);