Regulates the upgrading of configuration from one application version to the
next.
The process of upgrading will take a look at all profiles, preferences and
machine instances and check their version numbers. If they are older than
the current version number of their respective type of file, an upgrade
route will be planned for it in order to upgrade the file to the current
version in as few conversions as possible.
To this end, the upgrade manager will maintain the shortest routes to the
current version for each of the types of profiles and each old version it
encounters. Once a shortest route is found, it is cached and can be re-used
for all nodes along this route. This minimises the extra start-up time
required for the conversions.
Old versions of the configuration are not deleted, but put in a folder next
to the current (upgraded) versions, where they are never loaded again unless
the user manually retrieves the files.