diff --git a/docker/Dockerfile b/docker/Dockerfile
index de21bee..e49f802 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -12,6 +12,6 @@ RUN chmod 755 /opt/scripts/*.sh
 # Expose port 380
 EXPOSE 380
 
-ENTRYPOINT /bin/sh -c 'trap exit TERM; while :; do /opt/scripts/1-renew-cert.sh ; sleep 12h & wait \${!}; done;'
+ENTRYPOINT /bin/sh -c 'trap exit TERM; while :; do /opt/scripts/1-renew-cert.sh ; sleep 12h & wait $(jobs -p); done;'