If you HAVE PREVIOUSLY PUBLISHED an Android-Crosswalk app built with CLI 4.1.2 or earlier to an Android store this change may impact your ability to publish a newer version of that same app! In that case, add 6000 or 2000 respectively(six with three zeroes) to your existing App Version Code field in the Build Settings section of the Projects tab.
You can read more about this on Intel site here:
software.intel.com/en-us/xdk/articles/android-and-crosswalk-cordova-version-code-issues
Now, even if you're able to get this right, you'll run into a different problem; sort-of...
You see, CLI 5.1.1 is grate and all but your game is unplayable on Android 4.1, 4.2 and 4.3 unless you manually add this line to your intelxdk.config.additions.xml
<intelxdk:crosswalk xwalk-command-line="--ignore-gpu-blacklist" />
You can read more about this here:
software.intel.com/en-us/forums/intel-xdk/topic/606371
Now your game is grate again! :)