Could the update have been a way to act as a precursor of the upcoming Tier 3 boss rewards? When I mean precursor, I mean that the Darkfang Shield could have originally been suggested to be able to be bought with certain T3 boss tokens (see Blackened Crest). If so, we have a big update right at our fingertips.
They did say a new t3 boss, and herex clearly said that we'd meet again in the core, so we might have a non-dlc gremlin themed boss with fitting rewards
I doubt they would include a darkfang shield though, its a rare item and evidently intended to stay that way, if it were to be added with the boss, it might be a sort of 5* that can't be crafted up from the exclusive 4* version
If this update means they will release the boss soon, I dont know, but im not getting my hopes up, if you want to thats fine, ill leave people to their own optimism