Please read the release notes at https://github.com/JoinMarket-Org/joinmarket-clientserver/blob/master/docs/release-notes/release-notes-0.6.3.1.md for details on what this release includes.
Please verify the PGP signatures of the releases before using. They are signed with AdamISZ's pubkey (fingerprint: 2B6F C204 D9BF 332D 062B 461A 1410 01A1 AF77 F20B.
This will probably represent the last release of Joinmarket supporting Python 3.5 and lower. There are a couple of reasons for this:To support PSBT, BIP 78 Payjoin, SNICKER and related features, we are moving to a better developed Bitcoin library backed python-bitcointx , which requires Python 3.6 or later. Python 3.5 is in any case reaching end of life in September 2020, so very soon.
The upshot of this is that if you are running Joinmarket in an environment somehow constrained to not be able to run a recent version of Python, you may have to stick with this release (i.e. not upgrade past 0.6.3.1) for however long it takes for that situation to be changed. This is unlikely to cause any issues for people just wanting to do coinjoins and other basic wallet functions for quite a long time.
In terms of features, this release has a number of backend improvements and bugfixes, and some improvement in the UI of JoinmarketQt.
A binary (which you can simply download, verify the signature, and run without any installation/setup) of JoinmarketQt for Linux is made available; note that it hasn't been extensively tested across multiple distros, but should probably work on Debian and Ubuntu.