The deprecated log is fine.  We can't force folks to look at their logs sadly and it isn't a user message.  Unless someone wants to come up with yet another log category/file that will be ignored.

As for the B/C break, I'd argue it a bug fix based on the docblock: `@return  object   The object mapped from the given array` so a null return isn't an expected return.  @dongilbert care to comment?