Hej there,
could you implement Autocrypt in the next version of Evolution?
https://autocrypt.org/en/latest/details.html
It seems to make sending encrypted mails more easy. And i guess that needed to push non-technical people to use it as well.
My email provider already supports Autocrypyt - their blog article is unfortunately only available in German for now:
https://posteo.de/blog/neu-vereinfachte-e-mail-verschl%C3%BCsselung-mit-autocrypt-und-openpgp-header
But i guess you will get all the things you need on the Autocrpyt website/documentation.
Thunderbird with Enigmail and Android K9 App will support Autocrypt in their next versions too.
What about Evoulution?
Best wishes!