Sacrarium Solo Now?

I'm trying to get one of my mules through CoP so he can get reforged AF, and am currently on PM4-3. I thought I recently saw a post on Alla that said an update had made Sacrarium soloable.. but I can't find it anymore and wiki still says the mission is not soloable. Any help?

Thanks so much! <3

It's soloable providing you're at a high enough level to do so. But here's a clip from the latest update notes.

A new method for opening the door to Sacrarium has been added.
Trading a sealion crest key and coral crest key to Quelveuiat in Tavnazian Safehold (I-10) will provide the player with a Temple Knight key. While in possession of this key, players will be able to open the door by themselves by examining either the large keyhole or small keyhole in Sacrarium (H-7).
* Players must first complete the quest "A Hard Day's Knight" to utilize this new method.