I have read that 1Zpresso's K-series burr has received revisions and updates over the years and changed over time. Can anyone explain what exactly changed or how to tell which version of the burr you have?

I believe the earliest K-Plus grinders had a chamfered base at the bottom of the inner cone burr. That was then changed to a version with a base that was squared off, but still less wide than the burr diameter. Current K-Plus grinders seem to have a third base, one that's as wide as the burr itself. I don't know if the base says anything about the burrs themselves, but it is a visual difference I've noticed.

I have also heard about the outer burrs moving from the inside of the tube to a separate, screwed on ring.

I'm just wondering if anyone knows what updates were made to the K-series burr over time or know where I can find discussion about it.