That revision number should be good for testing islands. That's both BT and Dwilight.
Stable islands are indeed farther behind. I don't think there's any easy way to determine the rev level of a stable island. All code revisions have a rev number, including new features. So if a new feature is not moved to stable islands (like the the flagged messages), but a later bug fix *is* put on stable, then stable will be "missing" some revisions.
No, stable is on the same revision. That was one of the important points about moving to a full testing/stable setup rather than a testing-copied-to-stable setup.
However, occasionally we devs fix a bug in testing and forget to copy that fix to stable. If you notice something like this, just give a shout out (here or on the bugtracker) and we'll try and get to it quickly.
dev comment:
"Fixed in revision 5421." <--- but it's not... (and i'm talking about bt.)
This was the one about duchy taxes not showing up in your regional tax display (RegionTaxes.php), right?
Well, the revision in question definitely fixed something there, though it looks like it might have gotten a bit mixed up. I wasn't the one who fixed it, though, so I'll bring it up with the other devs.