@rsereno
I'm using v1.12.2, PHP 5.6, and MariaDB and I had 0 issues installing, configuring, and using the LDAP authentication plugin. No errors, no warning, etc.
Downloaded the plugin from https://osticket.com/download, moved the plugin to my server, moved it to the plugins directory, went to UI, installed the plugin, configured the Plugin, Enabled the Plugin, and was able to use the plugin without any issue.
SysInfo

Plugin

You do not need to hydrate, or do anything at all with the .phar
file. The only thing you have to do is move it to the include/plugins/
folder and go to osTicket UI to install it.
Cheers.