A few hours ago PlayStation posted a new blogcast discussing the PS4 software update 2.00, The crew has announced during the blogcast that themes would be available in the next update.
Now the blogcast is removed and corrected according to “Sid” one of the blogcast crew, Sid has confirmed on NeoGAF that the announcement made by error:
Hi guys – Sid from the Blogcast here, just wanted to confirm that this was in error and the show has been corrected. Sorry for the mixup! We’ll keep you posted on any news related to PS4 themes in the future.