According to DeeJ’s post on the official Bungie forum, Xur will be in the Tower until Monday at 10 p.m. PST.
The main reason for this decision are the connection issues on PlayStation Network and Xbox Live since Friday 26th.
Hey, Destiny Community.
We understand that Xur has been hard to reach for a lot of you this weekend, so we’re going to extend his stay. Our current plan is to allow him to remain in the Tower with his current inventory until Monday night at 10pm PST, just before the weekly reset. We’ll also keep an eye on the overall situation, and prolong the extension, as needed, for as long as is feasible.
Next week, Xur will return to his regular schedule, with refreshed inventory.