I finally decided to update to version 3.7.3 from 3.3.3 and I am wishing I hadn’t. There is an issue with files previously saved in the previous version. The volume is much lower when old recording are played back in 3.7.3. In 3.3 these were recorded and played back/showed as - 6.0 dB on the playback level meter. They are now only around -12.0 db maximum. Is there known incompatibility with old recordings with 3.7.4? On the left hand side there used to be a Gain and a Balance slider control. I had both these set at 0 on the old Audacity. The Gain is now labelled at Volume. If I slide this to -6 dB the volume of my old recordings does increase. Is this what you have to do now? I got -6 dB before with this set at zero
I do not have a real solution for your problem, but if you regret updating, you still can turn back.
Just download your preferred version (obviously 3.3.3) from Audacity’s site. There is a link to “older versions” on the main download site; it leads you to FossHub where you can find virtually anything.
Remember, if you do revert to 3.3.3, any project saved in 3.7.3 will not open in the older version.
Mark B
Yes, I saw the warning. So no going back 
As Mark pointed out, yes you can go back, but any project you have opened in 3.7.3 cannot be opened in earlier version, Forwards compatible, but not backwards There is a clear warning for this.
It kind of depends. If you have projects from 3.3.3 they will be OK. If you have finished projects saved in 3.7.3 you can export them to WAV and reopen them in 3.3.3. The issue arises if you have UN-finished projects created/saved in 3.7.3. Those ones are the problem. You’d have to re-apply your edits to an exported WAV, I guess. That’s how I THINK it works anyway.
I don’t know if that helps.
Mark B
The volume shouldn’t be getting changed… I don’t know what’s going on…
At some point the layout was changed and the recording & playback volume sliders are now “hidden” under the recording and playback meters.
Hmmm… I’m still seeing those in 3.7.3. They change what you hear and what you export but those changes don’t show-up in the waveform.