Downloaded .deb file from website. Once launched, the Install option is not present. Only Remove. Since this is a new version, Install should be an option (and always has been in the past).
I didn’t have that problem here (Kubuntu 21.04). Not very helpful, I know! I guess one thing to check is to confirm the current version of Mailspring you have installed.
Current version is 1.9.1, so this should be an upgrade. Not sure what is wrong. I installed Mailspring using the same method, but not sure I’ve upgraded since I’ve been on this distro.
If you installed via deb then you should be able to remove and reinstall the app safely (I believe). But if you used snap, be aware that any removal also removes your settings and preferences. (I’ve been caught by that one!)
I created a Timeshift restore point, removed Mailspring and reinstalled with the latest .deb. All good!! It keeps all of the accounts, preferences, etc.
