diff --git a/.arkindex.yml b/.arkindex.yml
index 276ff645ba654f67cb3c1f371d58768dc73f6152..a14027b7d3609537a193062ed6dcdc2096534ade 100644
--- a/.arkindex.yml
+++ b/.arkindex.yml
@@ -11,14 +11,14 @@ workers:
       build: Dockerfile
     user_configuration:
       train_folder_id:
-        type: str
+        type: string
         title: ID of the training folder on Arkindex
         required: true
       validation_folder_id:
-        type: str
+        type: string
         title: ID of the validation folder on Arkindex
         required: true
       test_folder_id:
-        type: str
+        type: string
         title: ID of the testing folder on Arkindex
         required: true