calendar of scheduled maintenance?

[heracross77]

Is there a calendar somewhere that tells us when scheduled maintenance takes place? To me it looks like scheduled and unscheduled maintenance is the same thing unless scheduled maintenance really has a schedule somewhere.

 

[Mo05eman]

The only difference between scheduled and unscheduled maintenance is that unscheduled usually means that there is a serious problem that needs to be addressed (ex website stops loading, major exploits or bugs, viruses). Scheduled usually implies that there is another feature they want to add or fix that is not crucial to gameplay fuctioning.