diff --git a/openlch/__init__.py b/openlch/__init__.py
index 60de242..edbaff7 100644
--- a/openlch/__init__.py
+++ b/openlch/__init__.py
@@ -1,3 +1,3 @@
-__version__ = "0.5.2"
+__version__ = "0.5.3"
 
 from .hal import HAL
\ No newline at end of file
diff --git a/openlch/requirements.txt b/openlch/requirements.txt
index 39934f5..938c7b5 100644
--- a/openlch/requirements.txt
+++ b/openlch/requirements.txt
@@ -4,7 +4,7 @@
 websockets
 pydantic
 grpcio
-protobuf
+protobuf==5.28.2
 
 # For the CLI.
 click