The developer's website provides the facility to send an email to all of your users that have an email address recorded.  You should be aware that while we have worked with filtering software to minimise the spam "score" generated by emails sent from our servers it is possible that some users will find the email arrives in their spam or junk email folders, depending on how aggressively the filtering software they or their ISP use works.

An alternative is to use the reports function on the developer's website to get a comma separated list of email addresses so you can send the emails yourself.