Update instances of given apps.
Files in that subtree will be updated, including the file provided.
Instances will only be updated if their type chain ends in this subtree.
Update all instances of a collection of apps. The instances to be updated can be specified as a subtree, possibly the entire filesystem. Similarly, the collection of apps for which the instances shall be updated can be specified as a subtree, possibly providing a package file or a local application.
.Update method will be applied to all intances.
Note that packages will not be re-imported, nor will the changes be commited.
Create a dummy box app and an instance of it. Create a new version of the app. Create an .Update file in the old to update old versions to the new. Update all instances with os.updateInstances().