Let me add few words here.
We develop extra apps to enhance the functionality of the system and to give you and your users extra experience. They are based (usually) on API of the main platform but sometimes include additional logics and so on.
Same is done by the partners themselves - we have lots of stories of success in this case - some of the partners develop extra to find and filter thefts, some of them - to manage tokens and so on. All of that is about the upselling - you propose something, that makes you unique on the market and that enhances the chance for the client to stay with you instead of moving to another partner or product.
Lyrical part is over. Now to the case - we consider some of the apps as a point of NDA or if you allow - intellectual property of our company. That is why some of the source codes are available at GitHub and others are not (compare for instance - TachoView with MessagesManager).
In your case - yes, you can install whatever on your server. Even our applications. As long as source codes are on GitHub.
We from our end would unlikely pre-install them on the server of the partner (e.g. include that into the installation package) as it requires lots of additional enhancements to be done - nginx configuration, logging, handling and so on).
So feel free to examine pages of the apps (like this one - http://apps.wialon.com/?lang=en#messagesmanager ). If there is a link to GitHub -> download the sourcecode, move it to the server, add an nginx config, add some logs, make sure to not to forget to rotate them, check the availability and (as Nishad mentioned above) - add them in CMS.
Regarding your second question - currently more often releases of WL are senseless as we have no solid arguments in favour of this decision. Nobody knows, what will happen in future this year - so make sure to follow our weblog and social media and you surely won't miss the news.