unable to ssh into old server after client upgrade to Linux Mint 21

After upgrading my client machine to Linux Mint 21, I was unable to ssh into an old internal server of ours. Interestingly, Filezilla on the client machine was able to sftp into the old server. At first, I thought the keys in .ssh might have changed, but it was an upgrade and not a reinstall, so the old keys were still there. Then found this - https://stackoverflow.com/questions/73795935/sign-and-send-pubkey-no-mutual-signature-supported - and ssh worked when I added the parameter

ssh -o PubkeyAcceptedKeyTypes=ssh-rsa

So, probably the new client has RSA disabled, while the old internal server still uses RSA.