Here's the link to the current patch notes...
Quoted below for pet specifics (also summarized on our own WCP front page)
> Supercharge now provides a 125% damage bonus (was 150%), and its cooldown is now 4 rounds (was 3).
> Sprite Darter Hatchling – Evanescence and Arcane Blast have swapped ability positions.
> Nether Roach is now a real roach and can now survive the apocalypse.
> Battle Pet Bandages now stack to 25 and are Bind to Account.
> Battle-Stones now have a chance to be awarded from PVP Pet Battles.
> Pets whose color schemes change each time they are summoned have returned. Older pets with this behavior now have it back, as well as some newcomers.
> Pet levels will now only display on the map when pets are tracked.
> Taming the World now lists its reward correctly in the Achievements pane.
> Level-capped players will now have a chance to earn Lesser Charms of Good Fortune after winning a pet battle versus a pet within 5 levels of the highest level pet on their team. Higher-level pets will offer a better chance to earn a charm.
> Winning a pet battle versus a team within 5 levels of the player's highest-level pet will now award player experience.
> Fleeing a pet battle will no longer despawn the pet that was being battled, but doing so will now inflict some damage on the fleeing pet battle team.
> Disconnecting from a pet battle will once again respawn the pets you were fighting.
> Any pet that has been killed in a pet battle will now never respawn.
> A number of new pets can be found on the Isle of Lightning, including rare spawn drops, wild pets, and raid boss drops.
> Elite Battle Pets have been added to the game world. These rare pets will spawn alone against an entire team. A new quest has been added to track progress as these new pets are hunted down, and completing that quest will award the new Red Panda pet.
> Please note: Many of these changes have not yet come to the PTR, but will be available soon.