The collaboration framework in Magentrix has been enhanced in the Summer 2017 Release and is now called "Mingel". Direct (private) messaging is supported for Community Users and needs to be enabled for each security role. Employee Users will be able to use Direct Messaging in the future.
Enable Direct Messaging
To enable Direct Messaging, go to the Setup menu and select Security > Security Roles. Select the Security Role you want to enable, click the "Edit" button and then go to the tab "Other Settings". Under the Section for "Social Collaboration" check the checkbox for "Enable Direct Messages". Make sure you click "Save & Close" before going "Back to Application".
To Use Direct Messaging
To use Direct Messaging, the Community User go to My Profile (click on the User's Name in the upper right corner). Click on "Show My Messages".
To send a message, click on "New Message" and start typing the recipient's name. Add your message, file attachments or Poll and click send.
Up to 9 other users can be invited to participate in private messages.