Audacity 4.0 released

Version 4.0 of the Audacity audio editor has been released.

Notable changes in this release include a rewritten interface using Qt, ability to save user-interface layouts as "Workspaces", improvements in working with audio clips, and a new .aup4 project format. The release is not fully feature-compatible with the Audacity 3.x series; see the compatibility notes for a list of missing features.