You don’t have to download manually if you already have it installed, your Daedalus wallet will ask you to upgrade.
Release notes: https://daedaluswallet.io/release-notes/
- Memory usage 80% decrease.
- Network improvements.
- Faster syncing.
- Connecting to Network fixes.
- Block storage optimized some, but will be improved more with the next major release.
- Cardano REST API v1 included.
- No Linux build, but there will be one eventually.
- Release integrity can now be verified via PGP.
- Formal specification available.