I just upgraded to 1.15.1 after which a new ticket is created with the title osTicket Upgraded. The first link in this post contains a link to the changelog.
This link is broken it results in a 404 Not Found:
osTicket upgraded successfully! Please refer to the Release Notes (https://docs.osticket.com/en/latest/Developer%20Documentation/Changelog.html?highlight=notes) for more information about changes and new features.
Thanks for the report. Yes, we have since removed that section from the Documentation and it's just reference the Github Releases page now. The changes should be included in the next release. Please stay tuned.