Tomorrow, Monday, October 13th, the PlayStation Network will undergo scheduled maintenance between the hours of 1PM and 8PM ET. During this time, according to a post on the official PlayStation Community forums by a member of PlayStation Support, a series of back-end improvements will be implemented.
Although it is unclear what exactly the series of improvements entails, some have speculated that the scheduled maintenance could be related to adding support for features being introduced in the upcoming 2.0 update. Others have suggested the maintenance could address the sluggish performance of the friends list on PlayStation 4, or general stability as the holiday season approaches and an influx of new users will inevitably be looking to take their new machines online.
Thankfully, gamers will still be able to play online and connect to third party applications, according to Sony, as long as the user has signed into the PlayStation Network on any device since October 8th. The PlayStation Store, PlayStation Home, account management and registration, as well as Sony's own entertainment applications will be inaccessible during the maintenance period across all devices. To see when PSN is back online, you can check the status page online.
PlayStation Network has suffered downtime regularly over the past few months. In late August, a series of DDoS attacks by a group calling themselves the Lizard Squad took PSN offline for the better part of a day, and causing Sony to postpone its previously scheduled maintenance from August 25th to August 28th. Following that, in early September, high demand for Minecraft temporarily knocked the PlayStation Network offline. More recently, PlayStation Network experienced downtime on October 2nd, the cause of which was unknown, however, the service was restored a few hours after Sony acknowledged the problem.