diff --git a/src-ui/src/app/components/document-detail/document-detail.component.ts b/src-ui/src/app/components/document-detail/document-detail.component.ts
index 57cb36393..ddc6aadcc 100644
--- a/src-ui/src/app/components/document-detail/document-detail.component.ts
+++ b/src-ui/src/app/components/document-detail/document-detail.component.ts
@@ -146,7 +146,7 @@ enum ContentRenderType {
 
 interface IncomingDocumentUpdate {
   document_id: number
-  modified?: string
+  modified: string
 }
 
 @Component({
@@ -449,7 +449,7 @@ export class DocumentDetailComponent
     )
   }
 
-  private showIncomingUpdateModal(modified?: string): void {
+  private showIncomingUpdateModal(modified: string): void {
     if (this.incomingUpdateModal) return
 
     const modal = this.modalService.open(ConfirmDialogComponent, {
@@ -458,17 +458,11 @@ export class DocumentDetailComponent
     this.incomingUpdateModal = modal
 
     let formattedModified = null
-    if (modified) {
-      const parsed = new Date(modified)
-      if (!Number.isNaN(parsed.getTime())) {
-        formattedModified = parsed.toLocaleString()
-      }
-    }
+    const parsed = new Date(modified)
+    formattedModified = parsed.toLocaleString()
 
-    modal.componentInstance.title = $localize`Document was updated.`
-    modal.componentInstance.messageBold = formattedModified
-      ? $localize`Document was updated at ${formattedModified}.`
-      : $localize`This document was updated elsewhere.`
+    modal.componentInstance.title = $localize`Document was updated`
+    modal.componentInstance.messageBold = $localize`Document was updated at ${formattedModified}.`
     modal.componentInstance.message = $localize`Reload to discard your local unsaved edits and load the latest remote version.`
     modal.componentInstance.btnClass = 'btn-warning'
     modal.componentInstance.btnCaption = $localize`Reload`
diff --git a/src-ui/src/app/data/websocket-document-updated-message.ts b/src-ui/src/app/data/websocket-document-updated-message.ts
index 1c09a59d2..bd1fe9e52 100644
--- a/src-ui/src/app/data/websocket-document-updated-message.ts
+++ b/src-ui/src/app/data/websocket-document-updated-message.ts
@@ -1,6 +1,6 @@
 export interface WebsocketDocumentUpdatedMessage {
   document_id: number
-  modified?: string
+  modified: string
   owner_id?: number
   users_can_view?: number[]
   groups_can_view?: number[]
diff --git a/src/documents/plugins/helpers.py b/src/documents/plugins/helpers.py
index 1e2139aba..148426b81 100644
--- a/src/documents/plugins/helpers.py
+++ b/src/documents/plugins/helpers.py
@@ -108,7 +108,7 @@ class DocumentsStatusManager(BaseStatusManager):
         self,
         *,
         document_id: int,
-        modified: str | None = None,
+        modified: str,
         owner_id: int | None = None,
         users_can_view: list[int] | None = None,
         groups_can_view: list[int] | None = None,
diff --git a/src/documents/signals/handlers.py b/src/documents/signals/handlers.py
index f55876932..9f2d22c79 100644
--- a/src/documents/signals/handlers.py
+++ b/src/documents/signals/handlers.py
@@ -772,9 +772,7 @@ def send_websocket_document_updated(
     with DocumentsStatusManager() as status_mgr:
         status_mgr.send_document_updated(
             document_id=document.id,
-            modified=DRF_DATETIME_FIELD.to_representation(document.modified)
-            if document.modified
-            else None,
+            modified=DRF_DATETIME_FIELD.to_representation(document.modified),
             owner_id=doc_overrides.owner_id,
             users_can_view=doc_overrides.view_users,
             groups_can_view=doc_overrides.view_groups,