diff --git a/tools/check_for_upgrade.sh b/tools/check_for_upgrade.sh
index 1c63734ed..3ba70583d 100755
--- a/tools/check_for_upgrade.sh
+++ b/tools/check_for_upgrade.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env zsh
 
 function _current_epoch() {
   echo $(($(date +%s) / 60 / 60 / 24))