Please read the release notes at https://github.com/JoinMarket-Org/joinmarket-clientserver/blob/master/docs/release-notes/release-notes-0.9.7.md for details on what this release includes.
For details on how the tumbler algorithm has changed (including a fix to a bug in schedule generation that affected users using lots of mixdepths, and including a change in how the tumbler operates - so this is a must-read for users), see the heavily updated tumbler guide.
There is also an important fix that should reduce the number of coinjoins that fail due to spent utxos, in times when activity in JM is high.
UI, RPC API and installation improvements are also in this release. See notes for details.
A Windows binary for Joinmarket-Qt and gpg signature is provided, as usual.
The release now also includes OTS timestamp files of the gpg signatures provided, that can be verified using the opentimestamps client.