diff --git a/packages/server/src/common/command/recording-command.ts b/packages/server/src/common/command/recording-command.ts
index 4fecee7..c8e4bb6 100644
--- a/packages/server/src/common/command/recording-command.ts
+++ b/packages/server/src/common/command/recording-command.ts
@@ -33,7 +33,7 @@ export abstract class AbstractRecordingCommand<JsonObject extends AnyObject> imp
         const afterState = await this.getJsonObject();
         this.undoPatch = jsonPatch.compare(afterState, beforeState);
         this.redoPatch = jsonPatch.compare(beforeState, afterState);
-        this.postChange?.(afterState);
+        await this.postChange?.(afterState);
     }
 
     /**
@@ -65,14 +65,14 @@ export abstract class AbstractRecordingCommand<JsonObject extends AnyObject> imp
     async undo(): Promise<void> {
         if (this.undoPatch) {
             const result = this.applyPatch(await this.getJsonObject(), this.undoPatch);
-            this.postChange?.(result.newDocument);
+            await this.postChange?.(result.newDocument);
         }
     }
 
     async redo(): Promise<void> {
         if (this.redoPatch) {
             const result = this.applyPatch(await this.getJsonObject(), this.redoPatch);
-            this.postChange?.(result.newDocument);
+            await this.postChange?.(result.newDocument);
         }
     }
 
diff --git a/packages/server/src/common/operations/json-operation-handler.ts b/packages/server/src/common/operations/json-operation-handler.ts
index 0bd5079..44e1560 100644
--- a/packages/server/src/common/operations/json-operation-handler.ts
+++ b/packages/server/src/common/operations/json-operation-handler.ts
@@ -38,8 +38,8 @@ import { OperationHandler } from './operation-handler';
  * Has to be implemented in order to reuse the {@link JsonOperationHandler} API.
  */
 export interface JsonModelState<JsonObject extends AnyObject = AnyObject> extends ModelState {
-    readonly sourceModel: JsonObject;
-    updateSourceModel(sourceModel: JsonObject): void;
+    readonly sourceModel: MaybePromise<JsonObject>;
+    updateSourceModel(sourceModel: JsonObject): MaybePromise<void>;
 }
 
 export namespace JsonModelState {
@@ -62,7 +62,7 @@ export class JsonRecordingCommand<JsonObject extends AnyObject = AnyObject> exte
     }
 
     protected override postChange(newModel: JsonObject): MaybePromise<void> {
-        this.modelState.updateSourceModel(newModel);
+        return this.modelState.updateSourceModel(newModel);
     }
 }