Nick:

 

The 'Online' of Messenger is different from 'Online' of website .

 

So if an user don't open the Messenger , the user would be Offline .

 

The Offline Messages have a bug, We will publish a new update next week , include fixing that bug .

 

We also provide an API function to tell the user that , "he has new offline message , please open messenger to check it"

 

Regards , Terry .