Specifically, this operation, for each selected form definition:
Reads the latest version (or selected version [SINCE Orbeon Forms 2020.1]) of the published form definition, whether it is available or unavailable.
Loads the latest versions of the published section templates that might be associated with that form definition.
TODO: this needs fixing, see #3885
Upgrades the form definition markup to the latest format, as if loading it in Form Builder and saving it again.
Includes the latest section templates loaded above into the form definition.
Saves back the form definition, either as a new version or as the same version (see below for details).
Form data isn't upgraded in the database, and is always stored in the sameformat, which out-of-the-box is the 4.0.0 format (see the
`oxf.fr.persistence.*.data-format-version` property). Instead, for data is
"upgraded" when loaded, and "downgraded" when saved. This way we can have a
stable format in the database, and in memory have whatever format a given
version of Orbeon Forms prefers.
4.0.0
format even if the property above is set to a different value".