diff --git a/tempest/lib/common/jsonschema_validator.py b/tempest/lib/common/jsonschema_validator.py
index 1618175..5212221 100644
--- a/tempest/lib/common/jsonschema_validator.py
+++ b/tempest/lib/common/jsonschema_validator.py
@@ -18,7 +18,7 @@
 
 # JSON Schema validator and format checker used for JSON Schema validation
 JSONSCHEMA_VALIDATOR = jsonschema.Draft4Validator
-FORMAT_CHECKER = jsonschema.draft4_format_checker
+FORMAT_CHECKER = jsonschema.Draft4Validator.FORMAT_CHECKER
 
 
 # NOTE(gmann): Add customized format checker for 'date-time' format because:
@@ -39,7 +39,7 @@
         return True
 
 
-@jsonschema.FormatChecker.cls_checks('base64')
+@FORMAT_CHECKER.checks('base64')
 def _validate_base64_format(instance):
     try:
         if isinstance(instance, str):