Welcome to the Streamlit community, and thanks for sharing your deployment issue! 
This “E: Release file for bullseye-security/InRelease is expired” error is a known problem that can occur when the underlying Debian repositories used by Streamlit Community Cloud are updated or archived, causing apt-get to fail during the packages.txt installation step. This is not caused by your code or repo, but by changes in the upstream package repositories.
The most effective solution, as confirmed by multiple users, is to delete your app from Streamlit Community Cloud and redeploy it. This forces the platform to use the latest base image and repository configuration, which resolves the expired release file issue. If you continue to see the error after deleting and redeploying, wait a short while and try again, as the Streamlit team may still be updating their infrastructure to point to the new repositories. No changes to your requirements.txt or packages.txt are needed for this fix.
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