Sony has announced that it will be having a brief maintenance period for PlayStation Network’s messaging system tomorrow, April 21st.

News of this comes from PlayStation’s forums, where the company detailed the maintenance, which will take place tomorrow from 9:00pm until 12:00am PST. During this time period the following features will be unavailable on PlayStation 4, 3, Vita, and the PlayStation mobile app:

• Sending PSN messages
• Receiving PSN messages
• Deleting PSN messages
• Changing the group message title
• Adding members to a group message

All other PSN features will be unaffected during this time.