Using fake query parameters to identify resource versions

When setting the cache expiry headers to somewhere in the far future as to make browsers not hit your server again for a long time (practically forever), you need some way to get the browser to newer versions of your otherwise static files. So far I have used a pattern containing the version of the artifact as part of the path:

http://my.server/js/lib/v123/lib.js

I just noticed the Sonatype repository using a different scheme, which is more like this:

http://my.server/js/lib/lib.js?v123

The version number is stored in a query parameter in this scheme. I assume that this parameter is actually ignored as most webservers would do with static content.

The advantages I see in this approach are:

• updates can be done in-place (easier deployment, no need to keep multiple copies around)
• the target doesn't even have to be aware of the scheme
• the client could even go as far as generating a URL based on its revision, causing a retrieval for each of its upgrades, which would be too much but very safe
  

Disadvantages I see:

• any reference will always retrieve the newest version (which could break things subtly if for some reason old references are still around somewhere)
• (related to the one above) it's just not a proper URI since it identifies a resource with the query parameter (unless you consider the resource as spanning all versions and the versions different representations of it)
  
• I don't know if I trust all caches to handle the query part properly (I never even looked into that)

It's an interesting approach and I can see it being a lot easier to manage than having distinct directories for each version. It somehow doesn't feel right, though.