The maintenance update was officially released July 29, 2013 for both the BlackBerry Z10 and Q10 models. The link below highlights what the update will bring to your Blackberry Z10 or Q10 device. http://ca.blackberry.com/support/smartphones/blackberry-z10/software-updates/release-highlights.html?CPID=SOC_C_WW_IBB1375126781
I went ahead with the update on my loaner Z10 over Wi-Fi and everything worked flawlessly. It's a relatively long procedure though taking nearly an hour to fully complete. Everything remained intact, but it is advised to backup the device before proceeding with the update.