diff --git a/docs/IMPLEMENTATION_PLAN.md b/docs/IMPLEMENTATION_PLAN.md
index bfd5edf..78e3194 100644
--- a/docs/IMPLEMENTATION_PLAN.md
+++ b/docs/IMPLEMENTATION_PLAN.md
@@ -957,7 +957,7 @@ Web:        Store/GameState/, Components/Game/, Hubs/GameHub
 | ✓ | H7 | Integration | DayDetails Tabs | 3 |
 | ✓ | H8 | Features | Undo (unbegrenzt, ohne Redo) | 2 |
 | ✓ | H9 | Persistenz | DB Persistence & Recovery | 4 |
-| ☐ | H9b | Sync | SignalR komplett + Auto-Reconnect | 5 |
+| ✓ | H9b | Sync | SignalR komplett + Auto-Reconnect | 5 |
 | ☐ | H10 | Testing | Kern-Logik Tests | 2 |
 
 **Geschätzte Dateien: ~52 neue/modifizierte**