Season 2 crests used for upgrading gear will be turned into gray items in Patch 10.2! However, you can still use them for upgrading old gear.
On the 10.2 PTR, we noticed that crests and crest fragments from Season 2 used for gear upgrading will become obsolete. This affects the Drake’s Shadowflame Crest and fragments along with Whelpling’s Shadowflame Crest and Fragments.
However, the change is not inherently bad because you can still use them to upgrade Season 2 gear!
The Emerald Dream questlines offer item level 421 gear that can be upgraded to item level 437 with just Flightstones, so you will quickly forget about Season 2 crests and upgrading old gear!
Season 3 crests will be a currency and they won’t occupy valuable inventory space in Season 3, which is another plus!