diff --git a/src/viur/core/config.py b/src/viur/core/config.py
index 230f6581b..6945735fc 100644
--- a/src/viur/core/config.py
+++ b/src/viur/core/config.py
@@ -997,5 +997,5 @@ def _resolve_mapping(self, key: str) -> str:
 
 
 conf = Conf(
-    strict_mode=os.getenv("VIUR_CORE_CONFIG_STRICT_MODE", "").lower() == "true",
+    strict_mode=os.getenv("VIUR_CORE_CONFIG_STRICT_MODE", "").lower() != "false",
 )