diff --git a/script/hassfest/manifest.py b/script/hassfest/manifest.py
index 583cafc8161..c6f8f71f2d9 100644
--- a/script/hassfest/manifest.py
+++ b/script/hassfest/manifest.py
@@ -119,7 +119,7 @@ def validate_version(integration: Integration):
     Will be removed when the version key is no longer optional for custom integrations.
     """
     if not integration.manifest.get("version"):
-        integration.add_warning(
+        integration.add_error(
             "manifest",
             "No 'version' key in the manifest file. This will cause a future version of Home Assistant to block this integration.",
         )
diff --git a/tests/hassfest/test_version.py b/tests/hassfest/test_version.py
index 203042e79be..f99ee911a69 100644
--- a/tests/hassfest/test_version.py
+++ b/tests/hassfest/test_version.py
@@ -27,7 +27,7 @@ def test_validate_version_no_key(integration: Integration):
     validate_version(integration)
     assert (
         "No 'version' key in the manifest file. This will cause a future version of Home Assistant to block this integration."
-        in [x.error for x in integration.warnings]
+        in [x.error for x in integration.errors]
     )