Maintenance for the week of December 23:
· [COMPLETE] NA megaservers for maintenance – December 23, 4:00AM EST (9:00 UTC) - 9:00AM EST (14:00 UTC)
· [COMPLETE] EU megaservers for maintenance – December 23, 9:00 UTC (4:00AM EST) - 14:00 UTC (9:00AM EST)
The list that I've been referencing is this one. The author has been doing a good job of keeping it up to date.
In general, if a set has no condition (other than the number of set pieces) associated with it, it will always work. If it does have a condition, then you'll need to look at the list I sent above or the original patch notes.