Legacy version won't run on the older version of PsychoPy

I’m trying to convert an experiment written on 2024 Psychopy to one for 2021.2.3
I slected this version in the settings to create a legacy version but it doesn’t seem to work.

I get this error message even though I already used the “Use Version” setting and set it to 2021.2.3:

line 84, in useVersion

  • raise ValueError(msg.format(requestedVersion))*
    ValueError: Unknown version 2021.2.3
    Alert 4051:Experiment was built in a future version of PsychoPy (2024.1.3), we recommend either updating PsychoPy or changing the “Use Version” setting in Experiment Settings to this version.

OS (e.g. Win10): Windows 10
PsychoPy version (e.g. 1.84.x): 2021.2.3

Please could I confirm the steps you took.

Did you:

  1. Open the psyexp file in 2024.1.3
  2. Change the version in experiment settings to 2021.2.3
  3. Save the file to generate a legacy psyexp file
  4. Check the date and time of the legacy psyexp to ensure it has just been saved.
  5. Close PsychoPy 2024.1.3
  6. Open PsychoPy 2021.2.3
  7. Try opening the legacy psyexp file.

If you can get this far then the next step is to save the legacy file as a psyexp file without the legacy tag.

I did get this far. Would removing the legacy tag change anything about the functionality of the experiment? Also by “tag” do you mean in the naming of the file or is this tag somewhere else?

This may be a windows/mac problem. I noticed that on windows I don’t have the option to save the file under a different version of psychopy. The only options are the version I currenly am using and then a blank category - two options on the dropdown menu under experiment settings.

When I do this on my macbook I get a long list of psychopy versions to choose from. I used my mac to change the experiment settings to 2021.2.3 - then tried to open this legace version with the 2021.2.3 version of psychopy on a windows computer.

It continues to read it as a file from a future software.

Are most people who use PsychoPy Mac users? I find that the majority of the problems I encounter with psychopy happen only on windows computers an not on mac.

Is there a way to save it under a different version on a windows computer? Unfortunately I need it to work in windows - that’s what our lab uses to run experiments.