A new firmware for PS Vita, version 1.67, is available today. Little is known about it, as no official announcement has been made by Sony so far.
Thanks to OMightyBuggy for the heads up!
Update: this firmware seems to be only containing a minor for Japanese game Dream Club Zero, according to psvitagen.fr. So, nothing really interesting. Thanks to pomopop for the tip.

People contact me regularly to ask why I’m spending time hacking the PSP emulator of the Vita, rather than the Vita itself. Others are wondering why we haven’t seen a true vita hack yet. So, what’s the current status?