Upgrade in short:

* Backup your config.php
* download new or stable or beta package of ehcp, extract it,
* restore your config.php
* logout & login back
* restart ehcp daemon: /etc/init.d/ehcp restart

Do not forget to restart your ehcp daemon after upgrade:
/etc/init.d/ehcp restart

Original question:
Hi, how to upgrade without reinstall? I have some domains…