diff --git a/tool/release.sh b/tool/release.sh
index a8a94af67a..0988dc2a67 100755
--- a/tool/release.sh
+++ b/tool/release.sh
@@ -4,7 +4,7 @@
 EXTS='.tar.gz .tar.bz2 .tar.xz .zip'
 
 ver=$1
-if [[ $ver =~ ^([1-9]\.[0-9])\.([1-9]|[1-9][0-9]|0-(preview[1-9]|rc[1-9]))?$ ]]; then
+if [[ $ver =~ ^([1-9]\.[0-9])\.([0-9]|[1-9][0-9]|0-(preview[1-9]|rc[1-9]))$ ]]; then
   :
 else
   echo $ver is not valid release version