Since the PS4 OS/UI is built using HTML5 GTK webkit2 APIs and stable updates to Gnome/GTKwebkit occur every 6 months with the latest usually late September to October, we can expect lots of firmware updates around October. Since DLNA CVP2 certification starts in September for I assume the same reason and it's projected that DLNA CVP2 platforms will start selling late this holiday season it's possible we will see DLNA in the PS4 late this year.
There are 15 platforms undergoing certification at this time. Sony and Microsoft will not release DLNA on their game consoles till certified and
this time it's DLNA 2.0 not 1.0 - 1.5 as in the PS3. DLNA 2.0 with 3 box model, EPG, Content Sync, RUI, WPS, Media Formats, Scheduled recording, DRM, Metadata.
Vita hasn't gotten DLNA for the same reason yet even though at release (2011)
there were slides with DLNA mentioned. Vita as Playstation TV is unthinkable without DLNA. Imagine the PS4 able to share games on Playstation TV but not media and from design as well as the
XB1's supported DLNA file types, it's and I assume the PS4 are to be media hubs designed to support other STBs and handhelds in the home.
The XB1 announced in September, is getting DLNA in October but Microsoft is stressing TV/media features in the XB1 while Sony is stressing Game features in the PS4. There is also that Microsoft's WMDRM10 and Playready are part of the CVP2 certification so they have a head start.
DLNA in the PS3 is always loaded as part of the OS except when running games. The PS4 always has HTML5 loaded for the UI and DLNA should also be part of the core OS always in memory. If it's to support the DLNA 2.0 and 1.5's three box model required by DLNA CVP2 then
it has to be integrated into the OS at a low level which
supports rumors of suspend/resume and DLNA coming with Firmware 2.0. Metadata supporting DRM usage rules has to be part of the core player and with hardware codecs I assume the same player routines are used for DLNA, HTML5 <video> and Blu-ray.
For sure Share 2.0 features before the holiday season and Nov 15 is about the latest we should see that. Nov 18 for GTAV for the PS4 I think is so it's out after Share 2.0.