My question is simple: Does Upgrade tool upgrade home.ctp file syntax? If not, do I have to rewrite the file and all its functions?
What do you mean by “home.ctp file syntax”? And “all its functions”? Do you mean functions that it calls (and if so do you mean things in helpers, or things from third-party libraries, or stand-alone functions you’ve declared yourself elsewhere), or functions that you are declaring right in the template?