Found this at reddit:
https://np.reddit.com/r/bitcoinxt/comme ... identical/
It seems as if BitcoinXT version 0.11E will have support for the same 2 MB blocks that Bitcoin Classic has. So, the two flavors are interchangeable. This is great news - I like XT because of its mempool limiting features and because of the traffic shaping functionality. If XT is fully compatible with Classic, I may continue to run XT on my public nodes.
I welcome multiple, competing and cooperating, flavors of bitcoin that are developed and maintained by different groups of devs. Bitcoin development, until now, has been centralized, thus limiting the voice that node operators have. It seems as if we are moving towards a scenario where there are multiple codebases, that work on the same ledger. Absolutely wonderful!