CMDI 1.2 instance migration impact

	A	B	C	D	E	F	G
1	Implications for instance migration
2	topic		1.1	1.1 -> 1.2	1.2 -> 1.1	Lossless downgrade?	Remarks
3	Lifecycle management
4		Lifecycle management	-	Update schema reference to 1.2 version	Update schema reference to 1.1 version	Yes	Schema reference should be to downgraded version of 1.2 profile. Keep in mind https://trac.clarin.eu/wiki/CMDI%201.2/Migration/Component%20migration#a1.2-1.1-1.2roundtrip
5	Attributes
6		Mandatory attributes	Always optional	Keep existing attributes	Keep all attributes	Yes	Downgraded profile will have all attributes optional
7		Generic attributes	One namespace	Move @ref and @componentId into CMD namespace	Remove namespace from all attributes, rename custom ref and componentId	Yes	Custom attributes that clash with generic should be renamed in downgrade, e.g. c_ref
8	Vocabularies
9		Integration with CLAVAS	No external vocabularies	-	Remove all value concept links from elements	No
10	Header
11		Mandatory MdProfile	Optional MdProfile	Add MdProfile header item if not present. Derive from schema location.	-	Yes	If schema location not present, fail on upgrade
12		MdType for indicating collection status	?	?	?	?
13	Cues for Tools					Yes	Does not affect instance
14		Extended display information	-	-	-	Yes	Does not affect instance
15		Documentation on components and attributes	-	-	-	Yes	Does not affect instance
16		Localised documentation	-	-	-	Yes	Does not affect instance
17		Derived values	-	-	-	Yes	Does not affect instance
18	Schema sanity
19		General component schema consistency	-	-	-	Yes	Does not affect instance
20		Namespace per profile	One CMD namespace	Use namespace based on the MdProfile for the payload	Replace the profile specific namespace for the payload by the one CMD namespace	Yes
21	Resource proxies and references
22		Resource proxy references on elements	Only on components	-	Remove refs from elements	No	Is probably not going to be included in the specification
23		Allowing only a single references from a component (or element) to a resource proxy	Multiple references allowed	Remove multiple references	-	No	Upgrade: how to decide which reference to keep in case of multiple references? May not occur in reality. At root level, all references can be discarded. Theoretically prevents lossless rountrip from being guaranteed
24		Specification of resource relations	Part of Resources with ref1 and ref2	? Transform as decided	? Transform as decided	Uncertain	Details have not been decided on
25		Location of the IsPartOf list	Part of Resources	? Move and transform as decided	? Move and transform as decided	Uncertain	It has also been proposed to remove the IsPartOfList altogether and use resource relations instead
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