Today I implemented a message system for Wiimmfi:
* test.wiimmfi.de/messages
You can find a link in the navigation bar and at other places since >10 hours.

It is designed for notifications by the system about events (e.g. competitions). It supports the following features:

• Priority messages
  
• Seen flag
  
• Links
  
• Overwritable messages (message of same class overwrites old message)
  
• Direct messages to single user (e.g. answer about region assignment)
  
• Subscriptions for events (e.g new competition) and notifications (e.g. new region application).
  
• Available subscriptions depend on granted rights.
  
• Navigation bar support (you will see a sign).
  
• Easy interface with 2 php functions:
  function SendMessageToUser ( $uid, $class, $msg, $link = '' );
  function SendMessageByClass ( $class, $msg, $link = '' )
  

The number of messages is limited to 100 and the age to 90 days. Old messages will be deleted without warnings.

I changed the structure of the message system. The easiest and fastest way for me was to delete all existing messages.