A new Android 4.3 update has been reported live as early as yesterday...
Source: http://www.phonearena.com/news/A-new-Android-4.3-security-update-now-live-for-Nexus-devices_id46655
Source: http://www.phonearena.com/news/A-new-Android-4.3-security-update-now-live-for-Nexus-devices_id46655