Whenever we release a new stable version of Tor Browser, we write a blog post that details its new features and known issues.
If you started having issues with your Tor Browser after an update, check out blog.torproject.org for a post on the most recent stable Tor Browser to see if your issue is listed.
If your issue is not listed there, please check first Tor Browser's issue tracker and create a GitLab issue about what you're experiencing.