backportpackage has an outdated version format.
--- /dev/null
+#!/bin/sh
+set -eu
+PACKAGE=${1:-cockpit}
+TARGET=${2:-impish}
+POCKET="${TARGET}-backports"
+
+series_ver() {
+ ver=$(wget -q -O- http://de.archive.ubuntu.com/ubuntu/dists/$1/universe/source/Sources.xz | xz -d | grep-dctrl -n -sVersion -XP $PACKAGE | sort -u | tail -n1)
+ ver=${ver%~bpo*}
+}
+
+upload() {
+ cat ../${PACKAGE}*_source.changes
+
+ read -p "Upload? [y/N] " answer
+ if [ "$answer" = y ]; then
+ dput ubuntu ../${PACKAGE}_*_source.changes
+ fi
+
+ cd ..
+ rm *bpo*
+ rm -r ${PACKAGE}-*
+}
+
+mkdir /tmp/backport
+cd /tmp/backport
+apt-get source $PACKAGE
+cd ${PACKAGE}-*
+
+case "$TARGET" in
+ impish) VER=21.10 ;;
+ focal) VER=20.04 ;;
+ *) echo "Unknown target $TARGET" >&2; exit 1 ;;
+esac
+
+series_ver "$POCKET"
+[ ! -x debian/adjust-for-release ] || debian/adjust-for-release $TARGET
+dch --local ~bpo${VER}. --distribution $POCKET --force-distribution "No-change backport to $TARGET"
+dpkg-buildpackage -S -sd -nc -v$ver
+upload