Blizzard just posted the Patch Notes for 25.0, which sets up the launch of the March of the Lich King and includes a bunch of big changes!
Patch Notes: https://hearthstone.blizzard.com/en-us/news/23882860/25-0-patch-notes
Timestamps
0:00 Introduction
1:06 Death Knight Events
3:05 Battlegrounds
4:48 Mercenaries
5:22 Duels
10:59 Arena
11:30 Duplicate Cards
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News | Hearthstone | BIG PATCH NOTES!! Duels Bucket Change! New Event! Tons more!