[DaveBlake]

Yes the identified issue was fixed in 17.1.
You may have foud something new, or most likely it is a tagging issue.

I've tried music files with and without replaygain in Krypton 17.1 and its not working for me.

You are going to have to provide more details. Start with an example of a file tagged to set the replaygain to something, maybe also provide a link to a debug log of this file being played.