From the few engineers who have been lucky enough to examine the first examples arriving from construction in Spain (some via testing in the Czech Republic), I understand the standards are very different to the existing and the first/second class designation is being dropped. I think more single occupancy planned without the premium, is the plan. Initially there may be a 'soft' roll out with September being the planned changeover date.
Strange to think the last time I travelled on the current ones, which were new at the time, and a great improvement then, was a few weeks after they were introduced 35 years ago!