You can see the rationale for the change here.
Basically IEEE754 floats have a different binary representation for +0.0 and -0.0. Equality comparisons like =/2 ignore the sign (as expected by IEEE754). But now exact comparisons like the match operator and erlangs =:=/2 will return false.
In the few cases I had I change from the matching to a guard clauses and it was a quick and backwards compatible change. But I can understand it would be a bigger issue if you have many many cases to adjust.
