I understand that you probably wouldn't have read the whole guide from start to finish (probably best not to anyway) but when you follow all the steps, what you'll be doing is installing all the hacks and stuff, and then upgrading to 11.3 in the end anyway. So no matter where all of us start the guide at, we all end up at the same firmware in the end.
11.3 won't let you install the stuff, but once you've installed everything from a lower firmware, you're OK to then upgrade up to 11.3 and beyond in the future.