There will be two different maintenance periods over Winter Break where Blackboard will be unavailable. The first will be on Monday December 29 from 8am PST until no later than 4pm PST. During this time Blackboard will be upgraded to the October 2014 release. This is a maintenance release and there are no major user-visible changes to users.
The second maintenance time will be on Tuesday December 30 from 5am PST until 7am PST. During this time the database will be upgraded.