diff --git a/src/pypaperless/models/documents.py b/src/pypaperless/models/documents.py
index 938a75b..b125246 100644
--- a/src/pypaperless/models/documents.py
+++ b/src/pypaperless/models/documents.py
@@ -109,6 +109,7 @@ class DocumentDraft(
     storage_path: int | None = None
     tags: int | list[int] | None = None
     archive_serial_number: int | None = None
+    custom_fields: list[int] | None = None
 
     def _serialize(self) -> dict[str, Any]:
         """Serialize."""