diff --git a/lib/CompositionManager.php b/lib/CompositionManager.php
index ea9a3b3..85d81f5 100644
--- a/lib/CompositionManager.php
+++ b/lib/CompositionManager.php
@@ -582,6 +582,7 @@ class CompositionManager {
             $deviceAttachmentsChanged = $uploads !== [];
             $documentAttachmentsChanged = count($failed) < count($documents);
             if ($deviceAttachmentsChanged || $documentAttachmentsChanged) {
+                $composed['revision'] = (int)($composed['revision'] ?? 0) + 1;
                 $composed = $this->markRemoteDirty($composed);
                 $compositionChanged = true;
             }
@@ -616,6 +617,7 @@ class CompositionManager {
             ];
         }
         if ($compositionChanged) {
+            $result['revision'] = (int)($composed['revision'] ?? 0);
             $event = new CompositionSavedEvent($tenantId, $userId, $composition, (int)($composed['revision'] ?? 0));
             $this->events->dispatch($event);
         }
@@ -774,8 +776,10 @@ class CompositionManager {
             }
 
             unset($composed['attachments'][$identifier]);
+            $composed['revision'] = (int)($composed['revision'] ?? 0) + 1;
             $composed = $this->markRemoteDirty($composed);
             $result['disposition'] = 'removed';
+            $result['revision'] = $composed['revision'];
             return $composed;
         };
 
diff --git a/src/stores/mailCompositionStore.ts b/src/stores/mailCompositionStore.ts
index 17ea95d..718a34a 100644
--- a/src/stores/mailCompositionStore.ts
+++ b/src/stores/mailCompositionStore.ts
@@ -380,6 +380,10 @@ export const useMailCompositionStore = defineStore('mailCompositionStore', () =>
         source: attachment.source,
       }
     })
+
+    if (response.revision !== undefined) {
+      activeDraft.value.revision = response.revision
+    }
   }
 
   async function addAttachmentsFromDocuments(items: { identifier: string; name: string; mimeType?: string; size?: number }[]) {
@@ -432,6 +436,10 @@ export const useMailCompositionStore = defineStore('mailCompositionStore', () =>
       }
     })
 
+    if (response.revision !== undefined) {
+      activeDraft.value.revision = response.revision
+    }
+
     if (response.failed?.length) {
       mailUiStore.notify(
         response.failed.length === 1
@@ -462,8 +470,11 @@ export const useMailCompositionStore = defineStore('mailCompositionStore', () =>
     if (response.disposition === 'error') {
       console.error('[Mail][Composer] Failed to remove attachment:', response.error)
     }
-    
+
     delete activeDraft.value.attachments[attachment.identifier]
+    if (response.revision !== undefined) {
+      activeDraft.value.revision = response.revision
+    }
   }
 
   function queueSave(immediate: boolean) {
diff --git a/src/types/composition.ts b/src/types/composition.ts
index c311fa2..4e3cf3b 100644
--- a/src/types/composition.ts
+++ b/src/types/composition.ts
@@ -111,6 +111,7 @@ export interface CompositionAttachmentAddResponse {
     message: string
   }
   composition: string
+  revision?: number
   attachments: Record<string, CompositionAttachmentInterface>
   failed?: {
     identifier: string
@@ -131,4 +132,5 @@ export interface CompositionAttachmentRemoveResponse {
   }
   composition: string
   identifier: string
+  revision?: number
 }
\ No newline at end of file
diff --git a/tests/php/Unit/CompositionManagerTest.php b/tests/php/Unit/CompositionManagerTest.php
index 688e7c8..7037390 100644
--- a/tests/php/Unit/CompositionManagerTest.php
+++ b/tests/php/Unit/CompositionManagerTest.php
@@ -187,6 +187,7 @@ final class CompositionManagerTest extends TestCase {
         $this->assertSame('added', $result['disposition']);
         $this->assertCount(1, $result['attachments']);
         $this->assertSame([], $result['failed']);
+        $this->assertSame(1, $result['revision']);
 
         $attachment = $result['attachments']['attach-1'];
         $this->assertSame('documents', $attachment['origin']);
@@ -196,11 +197,58 @@ final class CompositionManagerTest extends TestCase {
         $this->assertSame(strlen('hello world'), $attachment['size']);
 
         $snapshot = $this->compositionStore->compositionFetch(self::TENANT_ID, self::USER_ID, $compositionId);
+        $this->assertSame(1, $snapshot['revision']);
         $this->assertSame('dirty', $snapshot['remote']['status']);
         $this->assertNull($snapshot['remote']['entity']);
         $this->assertNull($snapshot['remote']['error']);
     }
 
+    public function testAttachmentAddIncrementsRevisionOnSubsequentAdd(): void {
+        $compositionId = $this->stageEmptyComposition();
+        $documentsManager = $this->createStub(\KTXM\DocumentsManager\Manager::class);
+        $documentsManager->method('entityFetchBulk')->willReturn([
+            $this->makeEntity('default:personal:root:doc1', 'hello.txt', 'text/plain'),
+            $this->makeEntity('default:personal:root:doc2', 'world.txt', 'text/plain'),
+        ]);
+        $documentsManager->method('entityReadStream')->willReturnCallback(
+            fn(): mixed => $this->makeStream('hello world'),
+        );
+        $manager = $this->makeManager($documentsManager);
+
+        $manager->attachmentAdd(self::TENANT_ID, self::USER_ID, $compositionId, [
+            'identifier' => 'attach-1',
+            'origin' => 'documents',
+            'source' => 'default:personal:root:doc1',
+        ]);
+        $result = $manager->attachmentAdd(self::TENANT_ID, self::USER_ID, $compositionId, [
+            'identifier' => 'attach-2',
+            'origin' => 'documents',
+            'source' => 'default:personal:root:doc2',
+        ]);
+
+        $this->assertSame(2, $result['revision']);
+    }
+
+    public function testAttachmentAddDoesNotChangeRevisionWhenNothingIsAdded(): void {
+        $compositionId = $this->stageEmptyComposition();
+        $documentsManager = $this->createStub(\KTXM\DocumentsManager\Manager::class);
+        // documents_manager unavailable means the sourced attachment fails
+        // entirely, so no attachment is actually added to the composition.
+        $manager = $this->makeManager($documentsManager, documentsModuleEnabled: false);
+
+        $result = $manager->attachmentAdd(self::TENANT_ID, self::USER_ID, $compositionId, [
+            'identifier' => 'attach-1',
+            'origin' => 'documents',
+            'source' => 'default:personal:root:doc1',
+        ]);
+
+        $this->assertSame('error', $result['disposition']);
+        $this->assertArrayNotHasKey('revision', $result);
+
+        $snapshot = $this->compositionStore->compositionFetch(self::TENANT_ID, self::USER_ID, $compositionId);
+        $this->assertArrayNotHasKey('revision', $snapshot);
+    }
+
     public function testAttachmentAddFromDocumentsPartialFailure(): void {
         $compositionId = $this->stageEmptyComposition();
         $documentsManager = $this->createStub(\KTXM\DocumentsManager\Manager::class);
@@ -285,6 +333,45 @@ final class CompositionManagerTest extends TestCase {
         $this->assertStringContainsString('not installed or enabled', $result['failed'][0]['message']);
     }
 
+    public function testAttachmentRemoveIncrementsRevision(): void {
+        $compositionId = $this->stageEmptyComposition();
+        $documentsManager = $this->createStub(\KTXM\DocumentsManager\Manager::class);
+        $documentsManager->method('entityFetchBulk')->willReturn([
+            $this->makeEntity('default:personal:root:doc1', 'hello.txt', 'text/plain'),
+        ]);
+        $documentsManager->method('entityReadStream')->willReturn($this->makeStream('hello world'));
+        $manager = $this->makeManager($documentsManager);
+
+        $added = $manager->attachmentAdd(self::TENANT_ID, self::USER_ID, $compositionId, [
+            'identifier' => 'attach-1',
+            'origin' => 'documents',
+            'source' => 'default:personal:root:doc1',
+        ]);
+        $this->assertSame(1, $added['revision']);
+
+        $result = $manager->attachmentRemove(self::TENANT_ID, self::USER_ID, $compositionId, 'attach-1');
+
+        $this->assertSame('removed', $result['disposition']);
+        $this->assertSame(2, $result['revision']);
+
+        $snapshot = $this->compositionStore->compositionFetch(self::TENANT_ID, self::USER_ID, $compositionId);
+        $this->assertSame(2, $snapshot['revision']);
+        $this->assertArrayNotHasKey('attach-1', $snapshot['attachments']);
+        $this->assertSame('dirty', $snapshot['remote']['status']);
+    }
+
+    public function testAttachmentRemoveNotFoundDoesNotChangeRevision(): void {
+        $compositionId = $this->stageEmptyComposition();
+        $documentsManager = $this->createStub(\KTXM\DocumentsManager\Manager::class);
+        $manager = $this->makeManager($documentsManager);
+
+        $result = $manager->attachmentRemove(self::TENANT_ID, self::USER_ID, $compositionId, 'missing-attachment');
+
+        $this->assertSame('error', $result['disposition']);
+        $this->assertSame('attachment_not_found', $result['error']['type']);
+        $this->assertArrayNotHasKey('revision', $result);
+    }
+
     private function makeManager(
         Stub $documentsManager,
         bool $documentsModuleEnabled = true,