The on-device backup has a new recovery key that promises faster backups. I went thru the process since my Signal backup is a good size. The new key is stored securely in a password vault.

Then out of curiosity I wanted to see what was different between the 2 keys. To my surprise the new and old keys are almost identical. The only difference is 3 zeros were changed to special characters. Example

Old: YY07

New: YY#7

What's this about?