The biggest new feature of this version is a "dark mode". It automatically selects the best mode for you (light or dark) but users can also select the mode explicitly:
New Features
[79305f5] Add a new dark mode design (@javiereguiluz)
[287868c] Allow selecting multiple rows holding shift key in index view (@vlepeule)
[2eb7c0e] Added more tests (@michaelKaefer)
Bug Fixes
[4a5ced3] Readd "leave empty" checkbox for nullable dates and times (@michaelKaefer)
[62286dc] Fix showing paginator when entity needs permission (@michaelKaefer)
[fdc4e64][497fd47] Make CSRF Token Manager optional (@a-r-m-i-n)
[566359f] Update Symfony compatibility for 3.x & 4.x in README (@jmsche)
[9ad94ff][5262d5e] Misc. doc fixes (@sir-kain)