This is a “feature” that was intended to be incomplete and low level, as I attempted to preface in the background. This is work that’s being done with the goal of eventually being a part of some larger “Forward Compatibility for FDB” design, like you’ve laid out. I don’t really see log_version sticking around in the long term, as it should be superseded by something like the “minimum downgrade version” support. This chunk of the work is being done now to prevent incoming tlog changes from being the reason that one can’t roll back from 6.1.X to 6.0, if testing turns out that there’s nothing else blocking that. Once something like “minimum downgrade version” exists, transitioning off of log_version should be relatively easy.
Ah, this thread seems to suggest that the answer is yes, which I also hadn’t thought about yet. Thanks!