We have been eager to hear anything about the new challenge league, which should launch mid-June. From this news post we know that the announcement will be done on 2nd of June and if everything goes according to plan the league will be launched on June 19th.
With new leagues come new supporter packs and old ones get removed from the item shop, which means that the Delirium supporter packs will be gone soon. If you are a fan of the Delirium pack MTXs you should get your Supporter pack now.
If you are a gamer that loves lore you should check out that post by NickK_GGG about creating Synthesis lore.