Together with #366 it could be made part of Blaze 2.6.1. Thoughts?

Just a question for understanding, shouldn't they have thrown errors after backwards compatibility has been removed? Is there maybe still old code?

Why remove files entirely? Why not keep the tests but change the APIs used? Also Template.__define__ got removed entirely!! This is a breaking change for no reason. It's ok to remove UI.body and the likes since they've alternatives but not the rest! I think we should add it back.

This is the code for Template.__define__:

// XXX COMPAT WITH 0.8.3
Template.__define__ = function (name, renderFunc) {
  Template.__checkName(name);
  Template[name] = new Template("Template." + name, renderFunc);
  // Exempt packages built pre-0.9.0 from warnings about using old
  // helper syntax, because we can.  It's not very useful to get a
  // warning about someone else's code (like a package on Atmosphere),
  // and this should at least put a bit of a dent in number of warnings
  // that come from packages that haven't been updated lately.
  Template[name]._NOWARN_OLDSTYLE_HELPERS = true;
};

I'm fine with putting it back, but I would probably make a change and show some sort of a warning at the very least.

Great work 👏

@fredmaiaarantes @denihs this is also ready to be included in Blaze 2.6.1

Hey @StorytellerCZ, published in the new version 2.6.1-rc.1.