diff --git a/README.md b/README.md
index a8594c3..26567b4 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,8 @@
 Deploy ddclient.
 
+Tested with OS
+- AlmaLinux 9
+
 Example config:
 
     ddclient_tsig_public_key_base64: "you_base64_public_key_here"