After updating to thunderbird-45.4.0, enigmail reports it cannot find the gpg binary. Pointing it to /usr/bin/gpg or /usr/bin/gpg2, it says that the chosen file is no valid gpg binary. app-crypt/gnupg-2.1.15 (same with -r1)
Thank you for the report. I fear we need more details to find the real cause. Perhaps it is an upstram bug, but lets see. I could not reproduce this with mail-client/thunderbird-45.3.0 app-crypt/gnupg-2.1.15 What was your thunderbird version before the update? Can you report if it works for you with mail-client/thunderbird-45.3.0, please? Can you provide the log files from the installation, please?
You are right, in thunderbird-45.3.0 enigmail works without problems. So it seems thunderbird-45.4.0 is at fault here.
After closing and restarting thunderbird, the error occurred again. It definitely worked the first time because I successfully sent a (signed) test mail. So maybe it is not a problem with the new thunderbird, but something else.
I apologize. It turns out this is an user error. I had installed enigmail in my user profile in addition to the system-wide installation of enigmail. After starting thunderbird for the first time after updating it, enigmail works. But then on the subsequent startups, the user-profile extension will take over and apparently it has a bug or is outdated, whatever. I am closing this as resolved invalid.
