As for every release please find here the free to download binaries for 1.31.0 on ARM architecture (aarch64).
GHC used is version 8.10.7 from last august.
1.31.0 cardano-cli
1.31.0 cardano-node
As usual it still needs libsodium, unchanged if you were already using it, but available here if you are new to this. (check my other posts for more details).
Enjoy, and if you feel like thanking us you can delegate few ADA to [PIRAT], Yarh !