Not just scoping. The hoisting rules have changed. There's some discussion earlier in the comments regarding `typeof` no longer being safe to use with `let` and `const` declarations. `typeof` with a `var` before its declaration is fine because of hoisting, but with `let` produces a reference error.
I didn't even know there were "hoisting" rules - I put all my variables on one var line at the top of the file, then assign them later. Well, except for lately, function variables in JSDoc work better when the function-var is immediately assigned :-(