There is new emissions standards coming. EU6 version d
(temp is a short term interim level to allow time to meet tougher specs)
Probably not yet upgraded engine to meet it (or hasn't yet been tested), so have suspended new orders for a while from 7th April. Probably when it reopens will get latest version.
There is a rumour (unconfirmed) that EU6d (full spec, not temp spec) engines will only be available with DSG gearboxes, the extra control helps meet the tough emissions rules