I think the main change was the sponsor breeding bonus, which gives an extra (and much needed) stat boost to any pups born in sponsor breeding kennels with 100 in the skill. Also, any broken stats should have been fixed long ago, which means they're all capable of reaching 10x4. Some breeds or stats make themselves feel like they're broken still though.
I think special groom was added within the last three years. When you sponsor train and have to long groom, you'll want to use "Special Groom x 6" after endurance hits 145. This does all 6 individual grooms and makes long grooming go by much, much faster.
If you event, you'll want to know that adaptability and courage is only counted up to 250 in the stat. Some dogs have 1000+ in these stats, but they shouldn't do any better than a dog with 250 in those stats. Unfortunately, it appears that eventing is broken. If you choose to event, the most reliable ones are racing and weight pulling.
If you breed short lifespan breeds, keep in mind that dogs can't be leased within 8 weeks of their death date. So if your breed dies at 12, you have to stop training at 11.10.0 or else you'll have to sell your dogs to the breeding kennel so they can breed.
I don't know if you rescue much, but TrophyPups, Superpups, etc. aren't able to be rescued. They're categorized in with personal breeds, so until they're placed in their own template, they cannot be rescued.
I don't have any real tips for getting started up again, but definitely try to be active on the forums. If you're polite and active with the community, people will get to know you better and you'll feel more attached to it.
