Today FM's The Mix Up show featured an interview with The Edge where he outlines the work flow process. Currently the band has been focused on rehearsals for the up coming tour. While they are focused on the tour they have set aside time to push the next album out.
Finishing date are fluid, its hard to predict. They refuse to rush the process and the label of course will not force them to throw out another album before its completely ready.
The band has never released a "rushed" product and at this point why start now. The Edge said "We don't want to release anything that we haven't had a chance to really finish to our satisfaction."