I was able to easily and successfully change to gmx by setting up an account and changing the relevant settings. Since I used port 587 for lavabit, I kept it the same and everything is working.
GMX
Server URL: mail.gmx.com
Port: 25 (alternates: 465, 587)
From Address: the address you chose when signing up ([email protected]).
Username: the address you chose when signing up ([email protected]).
Password: the password you chose when signing up.
GMX
Server URL: mail.gmx.com
Port: 25 (alternates: 465, 587)
From Address: the address you chose when signing up ([email protected]).
Username: the address you chose when signing up ([email protected]).
Password: the password you chose when signing up.