Hello [name]! Thanks for joining the GMC. Before making any posts in the Tech Support forum, can we suggest you read the forum rules? These are simple guidelines that we ask you to follow so that you can get the best help possible for your issue.
My understanding is that going backwards to 1.4 is not supported, and I can't blame them for not supporting it. Use the lowest common denominator (i.e. 1.4) if collaborating, or if you desire to publish in the Marketplace, or whatever, and test in 2.0 by importing 1.4 projects. Fortunately 2.0 includes the license to use 1.4 as well, so it's there if needed. But don't expect an easy migration path backwards.