diff --git a/assets/build-deb.sh b/assets/build-deb.sh
index 861202ea..6e0fb8dc 100755
--- a/assets/build-deb.sh
+++ b/assets/build-deb.sh
@@ -10,7 +10,7 @@ DEB_NAME=${DEB_NAME:-kumomta-dev}
 CONFLICTS=kumomta
 [[ ${DEB_NAME} == "kumomta" ]] && CONFLICTS=kumomta-dev
 
-KUMO_DEB_VERSION=$(echo ${TAG_NAME} | tr - .)
+KUMO_DEB_VERSION=$(git -c "core.abbrev=8" show -s "--format=%cd.%h" "--date=format:%Y.%m.%d.%H%M%S")
 distro=$(lsb_release -is 2>/dev/null || sh -c "source /etc/os-release && echo \$NAME")
 distver=$(lsb_release -rs 2>/dev/null || sh -c "source /etc/os-release && echo \$VERSION_ID")
 export SOURCE_DATE_EPOCH=$(git log -1 --pretty=%ct)