Sounds like Cart Before The Ponies. Honestly not much, the biggest thing is the changelings are good now (except Chrysalis). The pony in the image is a part of a group led by Starswirl that planted the seeds to the Tree of Harmony, basically the creators of the Elements. This group was the focus arc of season 7. The arc for season 8 currently is that Twilight's opened up a friendship school that all species (like dragons and griffons) can attend.