Updated app python version - Do not see advanced options to be able to change Python version in streamlit settings

I connected my Github to Streamlit cloud to deploy my app. Originally the app was using python 3.7 (and was working fine), but I changed it to python 3.8 and updated the poetry poetry.lock and pyproject.toml in my Github repo accordingly (I also made some package version updates such as scikit-learn so that they are compatible with python 3.8).

However, I get an error when the app tried to update or I reboot it:

Installing dependencies from lock file

  SolverProblemError

  The current project's Python requirement (3.7.13) is not compatible with some of the required packages Python requirement:

    - scikit-learn requires Python >=3.8, so it will not be satisfied for Python 3.7.13

I can’t figure out where python 3.7 is specified (except in settings when I deployed the app initially).

When I got to the app settings, I don’t see any option for advanced settings to change to python 3.8 (I only see sharing and secret tabs).

You need to create a new application in order to use a different python.

Creating a new app worked. Definitely wish there was a way to update python versions without deleting and re-creating the app.

I was partly worried about breaking the URL link (since the new app has a new hash in the URL). But turns out this isn’t an issue (the shareable URL from the old app still takes me to the new app).

Customizable subdomains seem to be on their way. I don’t know what the current status is, though.