There's been a few things cropping up in this space recently. On the topic of "indicating that this might be an outdated version", I've not managed to figure out a better solution than either linking to an IPNS index of document versions (so, for humans, some text that says "this might be out of date; check [here]), or running an IPFS node in JS on the browser and then querying for a later revision. I guess I'm looking forward to when browsers integrate with Dat, IPFS etc. natively (Beaker and Firefox are already heading down this path), so that I can rely on a little bit of Javascript that queries `window.IPFS` or some such, instead of having to send something much more heavyweight to the client.
In the meantime, if anyone has any better ideas for solving that problem (rel=canonical to an IPNS entry? browser extensions?), I'm all ears :).
Yeah, that might be the only way to handle this reasonably in the short-term -- `if (window.IPFS) { fetch(revisionListFromAnIPNS).then(renderIt) }`... but my concern is that if the standard changes in the future and IPFS gets integrated into browsers/becomes `navigator.IPFS`/etc. -- then all those old, immutable pages are permanently going to check the wrong thing. Still, I guess that's a graceful degradation, because for people who don't have the extension today, they'd see the same behaviour.
Perhaps it's best to provide a link to a revision list as the default behaviour, with the window.IPFS test as a mildly nicer progressive enhancement. Cheers :).
In the meantime, if anyone has any better ideas for solving that problem (rel=canonical to an IPNS entry? browser extensions?), I'm all ears :).