Beastess, welcome back! Nice to see another beta tester here :)
When exactly did you leave? Did you get a chance to try battlefield and two battlefield specific pet species or not?
The major update are deviant colors. When your pet is born with the same recessive and dominant genes for color or pattern, there's a 10% chance that it will get a rare color instead of a regular one. They are available for Dragons, Unicorns and Rocs (plus 90 skins for each species!), and probably the rest of the species will get their deviant mutations too. You may check Skin Library to see the existing deviants. Rocs are especially fantastic with their altered lineart. Just check this guy (I love bearded vultures ^^):
Another big update is 3 new explore biotopes - desert, jungle and savannah, all with their own monsters and a couple of specific buildings in each.
Basically everything stays the same. Sometimes they run different events: exhibitions for the best pets with a certain trait, explore events "collect xxx of that rare gemstone to trade it for booster items", Kami events where you need to fulfill a number of objectives to get a unique pet.
They updated the base coloring of dragons just a bit but lineart seems to be the same.