ArenaNet has announced that with the next release, they will be making changes to attribute-selectable gear.
The majority of attribute-selectable equipment in the game will be updated to include all of the attribute combinations available to your account, based on the expansions you own. Legendary equipment will still have all attribute combinations available regardless of expansion ownership. There are, of course, exceptions: crafted backpacks, elite specialization gear, and raid/fractal attribute combinations will not have access to all possible combinations.
The attribute selections available from Assaulter’s, Defender’s, Healer’s, and Malicious attribute-selectable gear are also being adjusted. The goal of this change is to make it more obvious which attributes will be available in each prefix family (the post has a full listing of the changes).
Also, daily rewards obtained from fractals that provide a choice of ascended armor will now contain a choice of heavy, medium, or light attribute-selectable gear associated with their prefix (Assaulter’s, Defender’s, Healer’s, Malicious) instead of a long list of choices of gear limited to attributes available in the base game. This change will be retroactive and apply to any chests currently in player inventories.
When this change goes live, many pieces of attribute-selectable gear will reset. You’ll need to reselect the attribute combinations on your equipped gear and the gear in your inventory. If your equipped gear is affected, you will receive a hint reminding you to select attributes for it.
For all the details, visit the post here