diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 8a4ff5b..57e7e64 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -10,7 +10,7 @@ repos:
     hooks:
       - id: check-bash-syntax
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.910
+    rev: v1.16.1
     hooks:
       - id: mypy
         args:
diff --git a/ecs_logging/_stdlib.py b/ecs_logging/_stdlib.py
index 33536bb..28e9f13 100644
--- a/ecs_logging/_stdlib.py
+++ b/ecs_logging/_stdlib.py
@@ -46,10 +46,6 @@
     _LOGRECORD_DIR = set()
 
 
-def _converter(secs: Optional[float] = None) -> time.struct_time:
-    return time.gmtime(secs)
-
-
 class StdlibFormatter(logging.Formatter):
     """ECS Formatter for the standard library ``logging`` module"""
 
@@ -77,8 +73,7 @@ class StdlibFormatter(logging.Formatter):
         "process",
         "message",
     } | _LOGRECORD_DIR
-
-    convert = _converter
+    converter: Callable[[Optional[float]], time.struct_time] = staticmethod(time.gmtime)
 
     def __init__(
         self,