Let me rephrase my question, I am not looking for help from the community unless someone here knows what endpoint I can hit to get the latest stable release version. I assure you we have been down all the workaround paths.
If this truly does not exist then I want to recommend to the Nextcloud team that when they are pushing a stable release they also push something like https://download.nextcloud.com/server/releases/stable.json containing either a download URL or a version.
Or if you want to keep this in Github then publish real github releases for your current stable releases and pre-releases for your betas/old major tags, so people can consume this stuff in a sane manner. (Github Tags are not guaranteed to be returned in order and all blend together as is)
Even if this is semi manual, we on the build side really need a simple file with a version number in it.
Thanks for the info, I will setup something to grab out of that file in github.
The setup you have requires the client passes a long complex string to the update server which specifies the exact version the client is running.
Why not take simple strings also for external consumption vs just in app IE: version=stable or version=15.x