diff --git a/conmon.spec b/conmon.spec
index 81c1b99..d52f6e7 100644
--- a/conmon.spec
+++ b/conmon.spec
@@ -8,12 +8,12 @@
 %endif
 
 %global built_tag v2.1.4
-%global built_tag_strip 2.1.4
+%global built_tag_strip %(b=%{built_tag}; echo ${b:1})
 %global gen_version %(b=%{built_tag_strip}; echo ${b/-/"~"})
 
 Name: conmon
 Epoch: 2
-Version: 2.1.4
+Version: %{gen_version}
 License: ASL 2.0
 Release: %autorelease
 Summary: OCI container runtime monitor