Reminder: Account Migration has NOT begun. You will receive notification in Minecraft Launcher or on Minecraft.net/profile when it’s your turn. Do not share info on any site until you've received notification via launcher. We will NEVER ask for personal information via email.

So, I bought Minecraft Dungeons back when it was preorder, and I didn't have time to play it until recently. However, now the original launcher has been discontinued, and it doesn't show as purchased in the Minecraft launcher. How do I play it? My accounts aren't migrated yet.