diff --git a/requirements.txt b/requirements.txt
index e5543fc..944825f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-pymodbus>=2.4.0
+pymodbus==2.5.3
 dpkt>=1.9.4
 configparser>=4.0.2
 requests>=2.25.1