As of 2018 we have changed our support-platform, and now issue all mails through Intercom. This means that mails from addresses like: 

are in fact mails from Jottacloud (support or simply information about updates, new features, payments etc.) and not spam.

Some of our e-mails will also contain hyperlinks to our webpage. We're using a mailingservice named Mandrill to send out e-mails. This will cause the hyperlinks to have a URL such as:
​https://mandrillapp.com/track/click/XXXXXXXX/www.jottacloud.com[...]
These links are safe, and will only redirect you to our homepage, and let us see how many recipients have clicked the hyperlinks.

Make sure to whitelist mails from these domains/addresses so that you don't miss important updates or information from us!