diff --git a/hbd/__init__.py b/hbd/__init__.py
index f504cee..19c8c5c 100644
--- a/hbd/__init__.py
+++ b/hbd/__init__.py
@@ -14,4 +14,4 @@ Install options:
 """
 
 __all__ = ["__version__"]
-__version__ = "5.1.20"
+__version__ = "5.1.21"
diff --git a/pyproject.toml b/pyproject.toml
index 7376f46..93f16bd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "hbd"
-version = "5.1.20"
+version = "5.1.21"
 description = "Heartbeat monitoring system — client (hbc) and server (hbd)"
 readme = "README.md"
 requires-python = ">=3.11"
diff --git a/scripts/hbc_mini.py b/scripts/hbc_mini.py
index 11e022b..5114e7a 100755
--- a/scripts/hbc_mini.py
+++ b/scripts/hbc_mini.py
@@ -41,7 +41,7 @@ from pathlib import Path
 from typing import Any, Dict, List, Optional, Tuple
 
 # updated by scripts/bumpminor.sh
-__version__ = "5.1.20"
+__version__ = "5.1.21"
 
 # ---------------------------------------------------------------------------
 # Protocol  (mirrors hbd/common/proto.py)