I doubt them letting us give back our characters until 2.0 is released because that would make the character info transfer pointless. However, they stated that there is going to be a 1.23a and a 1.23b today. Lets say 1.23b is in early-September, I'm going to guess that the current version will shut down by late-September/early-October. Though that means that the current version will probably be shut down until either Open beta or launch. However I kind of expect Open beta to only last 1-2 weeks.