Deployment problem - proxy caching old versions

[Guest trefgare]

We're having the following problem when deploying changes to existing javascript files.Some users are reporting errors that seem to be related to the updated versions being cached somewhere. We ask them to clear their local cache but this does not resolve the situation. Generally these issues resolve themselves after a week which leads us to believe that proxy caches are storing the files and not realising there's been an update.Is there some way to force a proxy cache to update a file? We're currently trying by adding a query string param to the end of each include e.g.<script type="text/javascript" src="/js/myScript.js?v=6.5.2" />however while this seems to have helped in some cases the issue is still happening for some users.Is there any other "secret squirrel" method of ensuring the cache believes it's a new file?Many thanks.