Starting July 30th, you will no longer be able to log in to a Curse account that was not merged with a Twitch account. If you have not yet merged your Curse account with a Twitch account, please do so here! Otherwise, your account and its content will be inaccessible.
"As part of ongoing communication with the WoW developers, it has been agreed that Hearthstone is now the official source of WoW lore. We hope you look forward to seeing Ragnaros, Lightlord in Legion!"