Full patch notes are here

[NorthernLadMSP]

I believe DL drops in the 3 new dungeons. But a fresh lvl50 should be able to easily run WP and the even-more-nerfed AK for myth tomes for ilvl90 armour.

I doubt that. According to the notes, the three new dungeons are also part of a Duty Roulette Extreme, which would be harder than Haukke HM, Sirius, Copperbell HM. I doubt you would have to get into these "extreme" dungeons just to get darklight. But, I could be wrong.