Bitcoin Core version 31.1 is now available from:

https://bitcoincore.org/bin/bitcoin-core-31.1/

For the release notes please see the git repository:

https://github.com/bitcoin/bitcoin/blob/master/doc/release-notes/release-notes-31.1.md

Do not use the links provided by GitHub. Use the above download links instead, as they are guaranteed to be generated deterministically and signed.