If you’re playing on desktop and you’ve seen a patch rolling out – no reason to worry, it hasn’t actually changed anything and you didn’t miss it. It was pushed out to fix some performance issues (mainly for Battlegrounds), and the same patch should be out on mobile tomorrow.
Balance update is still coming this week, and we should learn more about it very soon.
Edit: Update should be rolling out on mobile now too!
We’re currently putting out an update with various performance improvements for Hearthstone (especially for Battlegrounds). This update is live on desktop today, with the mobile update rolling out tomorrow.
As a side note, balance changes are still coming later this week. Stay tuned!