Audacity® is free, open source, cross-platform audio software for multi-track recording and editing.
November 2nd, 2017: Audacity 2.2.0 Released
Major new features:

Four supplied user interface themes, and customizability of themes for advanced users (thanks to James Crook and the Dark Audacity project)
Playback of MIDI files (fully automatic on Windows; requires cooperating software synthesizer programs on macOs or Linux; special thanks to Audacity co-founder Roger Dannenberg and new contributor “pokechu22”)
Better organized menus (James)
Help link buttons in many dialogs lead to the relevant Manual pages (James Crook and Steve Daulton)
Thorough update of the Manual with new images, more hover texts, and more cross-references
198 bugs/annoyances in 2.1.3 fixed, most importantly:
Improved recovery from full file system errors; in case of recording, Audacity 2.2.0 will preserve as much of the recorded data as possible
Complete support for macOS 10.12 (Sierra) correcting the problems that were in 2.1.3

See updated Manual and Release Notes for details.
Thanks to all involved in making this release, especially translators and testers who don’t normally get enough thanks for the work they