It might be better if you contact us directly via support ticket - https://support.springsignage.com/
Just briefly here:
Windows and CMS player and both distributed under AGPLv3 open source licence.
You can download and use them for free, you can also make modifications to the code with some responsibilities - http://xibo.org.uk/legal/
Spring Signage offers white label services for CMS and both players, if you’d be interested please contact us directly.
Xibo for Android is for android devices.
On-premise (offline) licencing module is also for android devices, the most common use of it is in the situation where android devices are permanently cut off from the internet - Licencing your Xibo for Android Display