I've just purchased Canary Mail to replace AirMail (a great app) so that I am able to sign and encrypt emails. I have tried to add my exported private keys to the app but fails both in iOS and MacOS.
I get the exception "Failed to read keys with exception: Invalid s2k identifier"
I exported my keys using: gpg --export-secret-key -a
You can see that I have 3 private keys, sign, auth and cert with my main key removed - these are what I class as my 'laptop keys'
Also notice that my main public key (keybase and server) 256E/7E40D9F9 is not listed