Audacity 3.1.3 was released on 23. Dec 2021.
Audacity 3.1.3 is a patch release for Audacity 3.1.
It improves the following aspects:
Added snap guides when resizing clips #2066
Added new shortcuts for looping: Shift+L for "Set Loop to Selection", Shift+Alt+L for "Clear Looping Region" #2209
Added a new selection region indicator in the timeline (identical in function as the one found pre-3.1, but with updated visuals) #2067
Changed error messages to look less like a crash report #2178
Re-added the Quick Play indicator (green triangle and line) that got lost during 3.1.0 development #2122
Fixed Play-at-speed not updating the playback speed dynamically #2149
Fixed looping regions being created unintentionally when attempting to use Timeline Quick Play #2182
Fixed looping sometimes playing the wrong audio #2103
Fixed a bug that could cause data-loss when joining multiple clips #2226
Fixed scrub preview visibility #2294
Fixed a bug when trying to locate FFMPEG manually #2282
Fixed a glitch with Loop Playback #2314
Fixed a crash when releasing a clip handle #2147
Fixed a freeze when closing Audacity with the logging window open #2114
Fixed a crash when loading a saved project using certain compilers #2216
Fixed a crash on paste after running macros #2021
Fixed a crash when cancelling a nyquist prompt #2239
Windows
Audacity 3.1.x requires the CPU to support the SSE2 instruction set which should be available on any Intel hardware produced after 2001 and any AMD hardware produced after 2003.
To check what SSE levels your CPU supports, you can install CPU-Z.
If your hardware only supports SSE, you may download Audacity 2.0.6 see the Legacy Windows page on the Audacity Website.
3.1.x does not support Windows XP.
You may try 2.2.2 on XP, but it is unsupported.
macOS / Mac OS X
Audacity 3.1.x is for Intel Macs running OS X 10.7 and later and macOS.
There are legacy versions for older OS X at http://audacityteam.org/download/legacy-mac/.
Linux
Linux support is tested on Ubuntu Linux.
Other Linux distributions should work, but aren't tested by the Audacity team.