Since upgrading to Yosemite, I have trouble running GPGMail with my Mac. When hitting the New Mail button Mail simply crashes.

There is little I can do, and I almost gave up. The logs don’t help that much, though.

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000

Application Specific Information:
*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<HeadersEditor 0x7fb0b6584680> valueForUndefinedKey:]: this class is not key value coding-compliant for the key _composeHeaderView.'
abort() called
terminating with uncaught exception of type NSException

However, there is this single thread in the GPG support forum, someone had the exact problem, while support pointed out there is some Yosemite beta of the GPG tools. Just in time,  GPG Suite Beta 4 was released, and it works like a charm.

In case you are looking for the public key, pick it up here.