Project information: Mailspring package is out of date with known security issues and outdated will no longer work with Google accounts.
The version in FH is 1.14 and on their Github it is 1.15.1
That’s wrong, the version is up to date com.getmailspring.Mailspring/com.getmailspring.Mailspring.yml at master · flathub/com.getmailspring.Mailspring · GitHub
Upstream just forgot to update their metadata