diff --git a/src-ui/src/app/components/document-detail/document-detail.component.spec.ts b/src-ui/src/app/components/document-detail/document-detail.component.spec.ts
index 925074a71..5a5c7966e 100644
--- a/src-ui/src/app/components/document-detail/document-detail.component.spec.ts
+++ b/src-ui/src/app/components/document-detail/document-detail.component.spec.ts
@@ -83,9 +83,9 @@ const doc: Document = {
   storage_path: 31,
   tags: [41, 42, 43],
   content: 'text content',
-  added: new Date('May 4, 2014 03:24:00'),
-  created: new Date('May 4, 2014 03:24:00'),
-  modified: new Date('May 4, 2014 03:24:00'),
+  added: new Date('May 4, 2014 03:24:00').toISOString(),
+  created: new Date('May 4, 2014 03:24:00').toISOString(),
+  modified: new Date('May 4, 2014 03:24:00').toISOString(),
   archive_serial_number: null,
   original_file_name: 'file.pdf',
   owner: null,
@@ -392,7 +392,7 @@ describe('DocumentDetailComponent', () => {
     jest.spyOn(documentService, 'get').mockReturnValue(
       of({
         ...doc,
-        modified: new Date('2024-01-02T00:00:00Z'),
+        modified: '2024-01-02T00:00:00Z',
         duplicate_documents: updatedDuplicates,
       })
     )
@@ -1214,7 +1214,7 @@ describe('DocumentDetailComponent', () => {
     })
     // simulate a document being modified elsewhere and db updated
     const remoteDoc = Object.assign({}, doc, {
-      modified: new Date(new Date(doc.modified).getTime() + 1000),
+      modified: new Date(new Date(doc.modified).getTime() + 1000).toISOString(),
     })
     jest
       .spyOn(activatedRoute, 'paramMap', 'get')
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 9e117d0ff..c430526e3 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
@@ -449,7 +449,7 @@ export class DocumentDetailComponent
     )
   }
 
-  private showIncomingUpdateModal(modified?: string | Date): void {
+  private showIncomingUpdateModal(modified?: string): void {
     if (this.incomingUpdateModal) return
 
     const modal = this.modalService.open(ConfirmDialogComponent, {
@@ -497,12 +497,6 @@ export class DocumentDetailComponent
     this.handleIncomingDocumentUpdated(pendingUpdate)
   }
 
-  private getModifiedRawValue(modified: string | Date): string | null {
-    if (!modified) return null
-    if (typeof modified === 'string') return modified
-    return modified.toISOString()
-  }
-
   private loadDocument(documentId: number, forceRemote: boolean = false): void {
     this.closeIncomingUpdateModal()
     this.pendingIncomingUpdate = null
@@ -613,7 +607,7 @@ export class DocumentDetailComponent
     }
     // If modified timestamp of the incoming update is the same as the last local save,
     // we assume this update is from our own save and dont notify
-    const incomingModified = this.getModifiedRawValue(data.modified)
+    const incomingModified = data.modified
     if (
       incomingModified &&
       this.lastLocalSaveModified &&
@@ -1089,9 +1083,7 @@ export class DocumentDetailComponent
       .subscribe({
         next: (docValues) => {
           this.closeIncomingUpdateModal()
-          this.lastLocalSaveModified = this.getModifiedRawValue(
-            docValues.modified
-          )
+          this.lastLocalSaveModified = docValues.modified ?? null
           // in case data changed while saving eg removing inbox_tags
           this.documentForm.patchValue(docValues)
           const newValues = Object.assign({}, this.documentForm.value)
diff --git a/src-ui/src/app/data/document.ts b/src-ui/src/app/data/document.ts
index 03d3bf09b..6300d737a 100644
--- a/src-ui/src/app/data/document.ts
+++ b/src-ui/src/app/data/document.ts
@@ -128,15 +128,15 @@ export interface Document extends ObjectWithPermissions {
   checksum?: string
 
   // UTC
-  created?: Date
+  created?: string // ISO string
 
-  modified?: Date
+  modified?: string // ISO string
 
-  added?: Date
+  added?: string // ISO string
 
   mime_type?: string
 
-  deleted_at?: Date
+  deleted_at?: string // ISO string
 
   original_file_name?: string