Hybris 5.3 and 5.7 differences / changelog?

The title gives away almost all information already. What are the differences between 5.3 and 5.7? Do changelogs exist?

Also i have been told that a lot of things changed in the data model and structure, and that we have some reconfigurations to do when changing (preparing for 6.0 as a lot of new features are not implemented in 5.3 but in 5.7)