diff --git a/lib/demo/demo-client.ts b/lib/demo/demo-client.ts
index 79b5fc67..f066c7fe 100644
--- a/lib/demo/demo-client.ts
+++ b/lib/demo/demo-client.ts
@@ -1046,7 +1046,7 @@ export class DemoJMAPClient implements IJMAPClient {
     const node: FileNode = {
       id: generateDemoId('file'),
       parentId, name, type: 'd', blobId: null, size: 0,
-      created: new Date().toISOString(), updated: new Date().toISOString(),
+      created: new Date().toISOString(), modified: new Date().toISOString(),
     };
     this.data.fileNodes.push(node);
     return node;
@@ -1056,7 +1056,7 @@ export class DemoJMAPClient implements IJMAPClient {
     const node: FileNode = {
       id: generateDemoId('file'),
       parentId, name, type, blobId, size,
-      created: new Date().toISOString(), updated: new Date().toISOString(),
+      created: new Date().toISOString(), modified: new Date().toISOString(),
     };
     this.data.fileNodes.push(node);
     return node;
@@ -1064,7 +1064,7 @@ export class DemoJMAPClient implements IJMAPClient {
 
   async updateFileNode(id: string, updates: Partial<Pick<FileNode, 'name' | 'parentId'>>): Promise<void> {
     const node = this.data.fileNodes.find(n => n.id === id);
-    if (node) Object.assign(node, updates, { updated: new Date().toISOString() });
+    if (node) Object.assign(node, updates, { modified: new Date().toISOString() });
   }
 
   async updateFileNodes(updates: Record<string, Partial<Pick<FileNode, 'name' | 'parentId'>>>): Promise<{ updated: string[]; notUpdated: Record<string, string> }> {
@@ -1072,7 +1072,7 @@ export class DemoJMAPClient implements IJMAPClient {
     for (const [id, patch] of Object.entries(updates)) {
       const node = this.data.fileNodes.find(n => n.id === id);
       if (node) {
-        Object.assign(node, patch, { updated: new Date().toISOString() });
+        Object.assign(node, patch, { modified: new Date().toISOString() });
         updated.push(id);
       }
     }
diff --git a/lib/demo/fixtures/files.ts b/lib/demo/fixtures/files.ts
index e4b3734c..59720d15 100644
--- a/lib/demo/fixtures/files.ts
+++ b/lib/demo/fixtures/files.ts
@@ -12,7 +12,7 @@ export function createDemoFileNodes(): FileNode[] {
       blobId: null,
       size: 0,
       created: demoDate(-30),
-      updated: demoDate(-2),
+      modified: demoDate(-2),
     },
     {
       id: 'demo-file-photos',
@@ -22,7 +22,7 @@ export function createDemoFileNodes(): FileNode[] {
       blobId: null,
       size: 0,
       created: demoDate(-30),
-      updated: demoDate(-5),
+      modified: demoDate(-5),
     },
 
     // Documents contents
@@ -34,7 +34,7 @@ export function createDemoFileNodes(): FileNode[] {
       blobId: 'demo-blob-file-1',
       size: 2150,
       created: demoDate(-7),
-      updated: demoDate(-2),
+      modified: demoDate(-2),
     },
     {
       id: 'demo-file-quarterly-report',
@@ -44,7 +44,7 @@ export function createDemoFileNodes(): FileNode[] {
       blobId: 'demo-blob-file-2',
       size: 148480,
       created: demoDate(-14),
-      updated: demoDate(-14),
+      modified: demoDate(-14),
     },
     {
       id: 'demo-file-todo',
@@ -54,7 +54,7 @@ export function createDemoFileNodes(): FileNode[] {
       blobId: 'demo-blob-file-3',
       size: 410,
       created: demoDate(-3),
-      updated: demoDate(-1),
+      modified: demoDate(-1),
     },
 
     // Photos contents
@@ -66,7 +66,7 @@ export function createDemoFileNodes(): FileNode[] {
       blobId: 'demo-blob-file-4',
       size: 1258291,
       created: demoDate(-10),
-      updated: demoDate(-10),
+      modified: demoDate(-10),
     },
     {
       id: 'demo-file-team-photo',
@@ -76,7 +76,7 @@ export function createDemoFileNodes(): FileNode[] {
       blobId: 'demo-blob-file-5',
       size: 911360,
       created: demoDate(-21),
-      updated: demoDate(-21),
+      modified: demoDate(-21),
     },
 
     // Root-level file
@@ -88,7 +88,7 @@ export function createDemoFileNodes(): FileNode[] {
       blobId: 'demo-blob-file-6',
       size: 68608,
       created: demoDate(-5),
-      updated: demoDate(-1),
+      modified: demoDate(-1),
     },
   ];
 }
diff --git a/lib/jmap/client.ts b/lib/jmap/client.ts
index d97ab234..cacef5eb 100644
--- a/lib/jmap/client.ts
+++ b/lib/jmap/client.ts
@@ -5534,7 +5534,7 @@ export class JMAPClient implements IJMAPClient {
   }
 
   private static FILE_NODE_PROPERTIES = [
-    "id", "parentId", "name", "type", "blobId", "size", "created", "updated",
+    "id", "parentId", "name", "type", "blobId", "size", "created", "modified",
     // Stalwart omits shareWith/myRights from FileNode/get unless requested
     // explicitly, so the share dialog and indicators can't see existing
     // shares without naming them here (same as CALENDAR_PROPERTIES).
diff --git a/lib/jmap/types.ts b/lib/jmap/types.ts
index e94dfba6..7ebdbfff 100644
--- a/lib/jmap/types.ts
+++ b/lib/jmap/types.ts
@@ -835,7 +835,11 @@ export interface FileNode {
   blobId: string | null;
   size: number;
   created: string;
-  updated: string;
+  // Last content/metadata change, server-maintained. The property is named
+  // `modified` in draft-ietf-jmap-filenode and in Stalwart - there is no
+  // `updated` on a FileNode. Asking for the wrong name silently yields
+  // undefined, which made the UI show the creation date forever (#700).
+  modified: string;
   // JMAP Sharing (RFC 9670). Populated only when the server advertises the
   // filenode capability and the properties are explicitly requested. A node is
   // shared-out when `shareWith` has entries; `myRights` describes what the
diff --git a/stores/__tests__/file-store.test.ts b/stores/__tests__/file-store.test.ts
index b22a4da1..7bf6151e 100644
--- a/stores/__tests__/file-store.test.ts
+++ b/stores/__tests__/file-store.test.ts
@@ -25,12 +25,12 @@ function makeMockClient(initial: FileNode[] = []) {
     },
     async createFileDirectory(name: string, parentId: string | null) {
       // A real folder has no content blob (this is how Stalwart marks a container).
-      const node: FileNode = { id: `n${++seq}`, parentId, name, type: '', blobId: null, size: 0, created: now(), updated: now() };
+      const node: FileNode = { id: `n${++seq}`, parentId, name, type: '', blobId: null, size: 0, created: now(), modified: now() };
       nodes.push(node);
       return { ...node };
     },
     async createFileNode(name: string, blobId: string, type: string, size: number, parentId: string | null) {
-      const node: FileNode = { id: `n${++seq}`, parentId, name, type, blobId, size, created: now(), updated: now() };
+      const node: FileNode = { id: `n${++seq}`, parentId, name, type, blobId, size, created: now(), modified: now() };
       nodes.push(node);
       return { ...node };
     },
@@ -92,15 +92,15 @@ function makeMockClient(initial: FileNode[] = []) {
 }
 
 const dir = (id: string, name: string, parentId: string | null): FileNode => ({
-  id, parentId, name, type: 'd', blobId: null, size: 0, created: '', updated: '',
+  id, parentId, name, type: 'd', blobId: null, size: 0, created: '', modified: '',
 });
 // An old build's "folder": a directory-typed node that is actually a blob-backed
 // file, so the server won't let anything be parented under it.
 const marker = (id: string, name: string, parentId: string | null): FileNode => ({
-  id, parentId, name, type: 'd', blobId: `b-${id}`, size: 0, created: '', updated: '',
+  id, parentId, name, type: 'd', blobId: `b-${id}`, size: 0, created: '', modified: '',
 });
 const file = (id: string, name: string, parentId: string | null): FileNode => ({
-  id, parentId, name, type: 'text/plain', blobId: `b-${id}`, size: 10, created: '', updated: '',
+  id, parentId, name, type: 'text/plain', blobId: `b-${id}`, size: 10, created: '', modified: '',
 });
 
 describe('file-store hierarchy (issue #379)', () => {
@@ -343,7 +343,7 @@ describe('file-store hierarchy (issue #379)', () => {
     // containers). The migration must detect this and undo its marker rename.
     (client as unknown as { createFileDirectory: typeof client.createFileDirectory }).createFileDirectory =
       async (name: string, parentId: string | null) =>
-        ({ id: 'bad', parentId, name, type: 'd', blobId: 'b-bad', size: 0, created: '', updated: '' });
+        ({ id: 'bad', parentId, name, type: 'd', blobId: 'b-bad', size: 0, created: '', modified: '' });
     useFileStore.getState().initClient(client);
 
     expect(await useFileStore.getState().migrateLegacyFlatNodes()).toBe(false);
@@ -373,3 +373,41 @@ describe('file-store hierarchy (issue #379)', () => {
     expect(client._nodes()).toHaveLength(0);
   });
 });
+
+describe('file-store modification date (issue #700)', () => {
+  beforeEach(() => {
+    useFileStore.setState({
+      client: null,
+      currentParentId: null,
+      currentPath: '/',
+      pathStack: [{ id: null, name: '' }],
+      resources: [],
+      selectedResources: new Set(),
+      clipboard: null,
+      lastAction: null,
+    });
+  });
+
+  it('shows the server-maintained `modified` date, not `created`', async () => {
+    // Stalwart names the property `modified` (draft-ietf-jmap-filenode); there
+    // is no `updated`. Asking for the wrong name used to leave lastModified
+    // pinned to the creation date, so replacing a file looked unmodified.
+    const client = makeMockClient([
+      { ...file('notes', 'Notes.md', null), created: '2025-01-01T00:00:00Z', modified: '2026-07-30T12:00:00Z' },
+    ]);
+    useFileStore.getState().initClient(client);
+
+    await useFileStore.getState().navigate(null);
+    expect(useFileStore.getState().resources[0].lastModified).toBe('2026-07-30T12:00:00Z');
+  });
+
+  it('falls back to `created` when the server sends no `modified`', async () => {
+    const client = makeMockClient([
+      { ...file('notes', 'Notes.md', null), created: '2025-01-01T00:00:00Z', modified: '' },
+    ]);
+    useFileStore.getState().initClient(client);
+
+    await useFileStore.getState().navigate(null);
+    expect(useFileStore.getState().resources[0].lastModified).toBe('2025-01-01T00:00:00Z');
+  });
+});
diff --git a/stores/file-store.ts b/stores/file-store.ts
index 28c255d7..ddd92314 100644
--- a/stores/file-store.ts
+++ b/stores/file-store.ts
@@ -174,7 +174,7 @@ function nodeToResource(node: FileNode): FileResource {
     isDirectory: isDir,
     contentType: isDir ? '' : node.type,
     contentLength: node.size,
-    lastModified: node.updated || node.created,
+    lastModified: node.modified || node.created,
     blobId: node.blobId,
     parentId: node.parentId,
     myRights: node.myRights,