Android 4.3 is finally here, and those of you who buy Nexus phones and tablets primarily for the fast updates won't be disappointed. Google is making the update available to almost every device supported by Android 4.2, and it's doing it starting today. Google's over-the-air updates for Nexus devices can take some time to roll out, though, so the impatient Nexus users among you are going to want to grab the official Android 4.3 images for all four supported Nexus devices from Google's factory images page. We'll include direct links here for your convenience.

• Android 4.3 for the Nexus 10 (codename "mantaray")
• Android 4.3 for the Nexus 4 (codename "occam")
• Android 4.3 for the Wi-Fi 2012 Nexus 7 (codename "nakasi")
• Android 4.3 for the 3G 2012 Nexus 7 (codename "nakasig")
• Android 4.3 for the GSM/HSPA+ Galaxy Nexus with Google Wallet (codename "takju")
• Android 4.3 for the GSM/HSPA+ Galaxy Nexus without Google Wallet (codename "yakju")

Android 4.3 has not been made available for the CDMA/LTE (read: Verizon and Sprint) Galaxy Nexus just yet. From past experience, you can bet that this update will take weeks or months to make it through their approval processes. Older Nexus devices like the Nexus S will not be supported by the new update, and the Google Play edition phones will get updates as their respective OEMs update their own Android kernels.
Installing these updates will fully wipe your device, but they may get you Android 4.3 faster than waiting for the update to come down through Google's software update mechanism. Several sites around the Internet have detailed manual installation instructions for Windows, OS X, and other operating systems—as long as you've downloaded the correct image, the process should be the same for all of the devices.
source :arstechnica