If you happened to catch the keynote speech yesterday during Google's annual I/O developer conference, you're likely already aware that they launched the third developer preview (of what is supposed to be five preview builds before the final public release) for Android N. While there may not be as many changes as there were with the first or second, there are some differences to note, one of which is that Android N is now considered by Google to be a beta, as Dev preview 1 and 2 have now been reclassified as alpha builds. Another change which some users may have noticed is that Android Pay now works with the Android N dev preview.
For those that are using Android N Preview 3, this is sure to be a beneficial improvement if Android Pay is compatible with their bank. This is also following a short string of changes to Android Pay itself, which saw the inclusion of support for Bank of America ATMs yesterday as well support for mobile web purchases. Prior to this version release for Android N, Google intentionally disabled Android Pay until things worked a little bit better with the software build and because there was no approval for the Compatibility Test Suite.
Now that CTS has been approved Google was able to flip the switch on Android Pay and make it available for use by anyone on the Android dev preview 3 software. If Android Pay was never your thing but you were waiting on the compatibility of other apps that needed CTS to work, those should be useable. Android Pay should work with any device that is able to install the third dev preview of Android N, but it is being reported that the Sony Xperia Z3 is still not able to use Android Pay with the dev preview even with this version build. Whether or not this is the case for every model of the phone that is running this version of the Android N build is unclear. If you use any device that can install Android N preview 3 and Android Pay is not working, you may want to consider going back to Marshmallow if Android Pay is an app you want to use.