Hello Lennart, 

 

The Translations folder you need is at SmarterTools\SmarterMail\MRS\App_Data\Translations. The en.json file and all other available translations are stored there. You can add translation files to your own installation and make adjustments to any of the files available. Let me know if you plan to create your own! I can send you over some guidelines.

Lennart, be aware that if you create your own language file or modify an existing language file, you need to make a copy of that file when performing an update to SmarterMail.  Since certain language files are included in the SmarterMail installation, any of your own modified files could be overwritten.