diff --git a/server/collaboration/persistence.js b/server/collaboration/persistence.js
index dcbff903..016f0db6 100644
--- a/server/collaboration/persistence.js
+++ b/server/collaboration/persistence.js
@@ -52,7 +52,7 @@ export default class Persistence {
       documentName,
     }: {
       document: Y.Doc,
-      context: { user: User },
+      context: { user: ?User },
       documentName: string,
     }) => {
       const [, documentId] = documentName.split(".");
@@ -63,7 +63,7 @@ export default class Persistence {
         await documentUpdater({
           documentId,
           ydoc: document,
-          userId: context.user.id,
+          userId: context.user?.id,
         });
       } catch (err) {
         Logger.error("Unable to persist document", err, {
diff --git a/server/commands/documentUpdater.js b/server/commands/documentUpdater.js
index 72de0acc..d9a845b2 100644
--- a/server/commands/documentUpdater.js
+++ b/server/commands/documentUpdater.js
@@ -13,7 +13,7 @@ export default async function documentUpdater({
 }: {
   documentId: string,
   ydoc: Y.Doc,
-  userId: string,
+  userId?: string,
 }) {
   const document = await Document.findByPk(documentId);
   const state = Y.encodeStateAsUpdate(ydoc);
@@ -38,7 +38,8 @@ export default async function documentUpdater({
       text,
       state: Buffer.from(state),
       updatedAt: isUnchanged ? document.updatedAt : new Date(),
-      lastModifiedById: isUnchanged ? document.lastModifiedById : userId,
+      lastModifiedById:
+        isUnchanged || !userId ? document.lastModifiedById : userId,
       collaboratorIds,
     },
     {