What action is appropriate in pre-existing but not yet C2PA labeled works

[Brianthered]

What action is appropriate for a pre-existing work? E.g. If I had created a movie in 2000 and I wanted to apply C2PA to it.

specifications/build/site/specifications/2.1/specs/C2PA_Specification.html

Line 9409 in 153a621

<h4 id="_mandatory_presence_of_at_least_one_actions_assertion"><a class="anchor" href="#_mandatory_presence_of_at_least_one_actions_assertion"></a>18.12.2. Mandatory presence of at least one actions assertion</h4>

[lrosenthol]

c2pa.opened - since you "open" and existing work to then apply the provenance.

But this is a good point that we should add this into our upcoming Guidance!