We need to establish app versioning for select applications.
Currently, most apps are just updated to the latest version. This does not account for those who want to use a specific version or may have upgrade issues which can only be easily resolved by having two separate app versions installed.
We do this with ownCloud and ownCloud 6 now. I anticipate this could apply to other apps in the future, such as Drupal, MediaWiki, etc.
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