My question says it all, but here's some background:
Due to various constraints I'm stuck on .NET 4.0 until at least July 2014. However, I'm tasked with converting our DAL to use Entity Framework for help with scalability and performance. Currently we load all data into memory from a single xml file so I'm looking at using Code First with our existing entities. We have a very large and complex model with lots of inheritance and enums and I'd really like enum support and performance improvements available with the newer releases.
So, do I starting working with EF6 now and hope it's official before our release date, start with EF4 then migrate? Or just wait until our next product release before starting with EF at all? Any advice is appreciated.