nice installer. Some suggestions

[miltosc]

works fine with debian 7.7 you can add the following safely i tested with no probs

50 #milt comment
51 #if [ "$OS" = "Debian" ] && [ "$VER" = "7" ] || [ "$VER" = "7.0" ] || [ "$VER" = "7.1" ] || [ "$VER" = "7.2" ] || [ "$VER" = "7.3" ] || [ "$VER" = "7.4" ] || [ "$VER" = "7.5" ] ; then
52 if [ "$OS" = "Debian" ] && [ "$VER" = "7" ] || [ "$VER" = "7.0" ] || [ "$VER" = "7.1" ] || [ "$VER" = "7.2" ] || [ "$VER" = "7.3" ] || [ "$VER" = "7.4" ] || [ "$VER" = "7.5" ] || [ "$VER" = "7.7" ]; then

in case that something goes wrong and user needs to execute again the install script

if user already downloaded from github zpanel and do not want to re-download it or ask to re-download and skip the git command if user does not want to do so

also there is sometimes problem with zadmin password it would be better to ask user to run setzadmin --set newpassword if he cannot login or save it to passwords.txt as an advice