You can find the full list here.
The main improvements in this first version of the new form are the ability to add login pages directly on the form + a better experience for conditional fields. Most of the improvements that were made have been infrastructural ones under the hood. This new form is rewritten from scratch and will give us the ability to build a much faster, more reliable, and more capable form. The foundation is now in place for us to be able to do that when it was not before in the old form. The first version that just got released is an initial version that mostly just implements most of the functionality of the old form, but we will be making many more releases in the upcoming months that will dramatically increase the capabilities of the form. This work is already underway but will take some time until it is released.