Is it possible to upgrade my TC55s from Android 4.4.3 (which is slow with javacript) to 6.0.1?

I've been building a mobile web app using jQueryMobile, AJAX, jQuery, and about 200 lines of custom javascript which has functions which change classes, attributes, or innerHTML. The entire webpage is only about 2k rendered. But on my TC55 test gun, Android 4.4.3, the Javascript functionality just crawls. I tried it out on my phone (Galaxy 5, Android 6.0.1) and it works great.


I need to roll this app out on about 15 TC55 guns, but it isn't working well enough now to bother. Is there any way to upgrade all my warehouse guns to a different version of Android? I did a search, and lots of other folks say that Android 4.4.3 doesn't play well with Javascript.