Season of Arrivals has begun in Destiny 2, and introduces the new Umbral Engram. This rather odd-looking Engram is covered with some black residue. You can’t open these at the Cryptarc, and instead will be relying on the Drifter to open them. You will need to play through the In the Face of Darkness quest.
Go and visit the Drifter after you return to the Tower with Eris Morn. The Drifter will ask you to take the Seed of Silver Wings, an item you got from Eris Morn in the previous mission, and complete the Contact Public event. You do not need to be successful in this event, you just need to complete it.
This public event is currently available on Io, as you can see in the image above. Just spawn in and Lost Oasis and then make your way there. Contact is a tough public event and plays out a little bit like Gambit. You need to kill enemies and collect the motes they drop, then deposit these in the bank.
Each full charge will spawn a wave of powerful enemies that you must defeat to move on to the next wave. This is a race against the clock, and if you get to the final part you will need to fight a boss to finish the event. Successfully finishing it will net you another Umbral Engram, and you will then need to return to the Drifter to find out the next step.
When the even is over, head back to the Drifter, and he will tell you to use his Umbral Decoder. This is located directly beside him, and will decode the Engram into an item for you.
That’s it, there is more to the quest, but you can now open the Umbral Engrams whenever you pick one up, all you need to do is bring it to the Drifter and use the Decoder.