DistributionNotFound --> version difference

I’m encountering the following error:
pkg_resources.DistributionNotFound: The 'platformio==3.4.0b10' distribution was not found and is required by the application

pip list shows platformio 3.4.0b11 so there’s a version mismatch. I’m only an end user with no “behind the curtains”-knowledge of Platformio.

What do I have to do to get this working?

Please remove %HOME_DIR%/.platformio/penv folder and restart IDE.