That info is best found in the release notes for each update, but the blogs usually cover the major changes as well:
Was there something specific you wanted to know about that you couldn't find when googling or reviewing the docs? If not, did the above link provide enough info?
The main product difference is that Framework Folders replace Contribution Folders as the default folder solution. This includes a new Desktop Integration Suite.
Here's a handy blog post about PS5: