The Battlefield 4 Summer Update should now be live on all platforms, along with the new, freeDLC pack.
You can find the Summer Updatehere. There's quite the laundry list of fixes and tweaks, including improved networking and the usual round of weapon balance adjustments.
As for Night Operations, it adds Zavod: Graveyard Shift, a reworked night version of Zavod 311 playable in Conquest, Rush, Obliteration, Team Death Match, Domination and Gun Master modes, plus improved night play, including the tactical removal of light sources.
If you've got your night-vision goggles ready, you can read DICE's guide to the new night operations