diff --git a/packages/gt-i18n/src/gt_i18n/internal/_load_gt_config.py b/packages/gt-i18n/src/gt_i18n/internal/_load_gt_config.py
index 4c088df..0ea1a72 100644
--- a/packages/gt-i18n/src/gt_i18n/internal/_load_gt_config.py
+++ b/packages/gt-i18n/src/gt_i18n/internal/_load_gt_config.py
@@ -16,7 +16,7 @@
     "cacheUrl": "cache_url",
     "runtimeUrl": "runtime_url",
     "customMapping": "custom_mapping",
-    "_versionId": "version_id",
+    "_versionId": "version_id",  # leading underscore intentional — matches gt.config.json convention for internal fields
 }