We have started the update for the database server so will be offline for at least several hours. I will be monitoring the situation and get everything back up as soon as possible.
First round of updates went smoothly with no downtime or issues. Tomorrow's update will cause downtime though. Probably 3-4 hours.
Linode, our hosting service, has upgraded their services and in order to take advantage of the upgrades we need to power down our machines. This first phase of this upgrade will occur on Saturday 4/19/2014, and will involve upgrading our frontend and apache clone. This should not require taking the site offline but could potential cause strange behavior or decreased performance.
The second phase will occur at 12:00pm EDT Sunday, 4/20/2014 and will require shutting down our database server. This will cause the site to go offline. We estimate that this should take 3-4 hours.
For more information on the upgrades see Linodes blog post.