You can fetch the latest master branch from https://git.zrythm.org/zrythm/zrythm and start testing the latest features. You can report any bugs, ideas and impressions by creating an issue there.
If you are on Arch Linux or Debian, the latest master branch can easily be installed via the zrythm-git package on AUR or by installing an auto-generated .deb file. More information at Installation Instructions.
Manual installation instructions can be found here.