hi there, yunohost works fine for my personal email !
I use it has primary email for my fedora contributions and use both k9mail and Thunderbird.
my problem is that emails sent with Thunderbird are invisible with k9mail and vice-versa.
is there any hint about how to solve this ?
by the way, share contact list would also be great !
use case : I send an email to tatarata@redhat.com, the address is remembered in thunderbird but no it k9mail
but it’s not a big issue 
How did you configure Thunderbird and K9mail ? Are you connected with imap or pop ?
For me, with imap, I can see the messages I sent with Thunderbird in “Sent” folder with K9Mail.
If you want see the messages you sent with K9Mail in Thunderbird, if you are connected with imap, you have to configure K9Mail so it can put a copy in “Sent” folder (parameters of your account --> Folders --> Sent folder)
Thanks for your answer, both are connected in imap and have in account settings, a sent folder configured (“Envoyés”)
if I noticed an explicit option to put a copy in “Sent” folder for thunderbird, I just had the possibility to select a folder in k9mail, I can’t find the copy part
Be careful with K9Mail, in the french interface, the default folder “Envoyés” is not the same as “Sent”, wich is the imap folder. You just have to select this folder.
it indeed solved the problem, thank you !
I’ll think to make a bug report in k9mail !