General guidance on version upgrades

[ColinMaudry]

With the release of OCDS 1.2, many data publishers will wonder how to upgrade, the available options, the potential side effects etc.

The revision and upgrade process is well documented in Governance from a standardization point of view, but not from a data publication point of view.

[jpmckinney]

From #849 (comment), we can mention the possibility to publish several datasets for different OCDS versions.

Also from #849, we should be clear that when upgrading a source (API, bulk downloads, etc.) then all data from that source should be upgraded to the same version. (Publishers can of course have endpoints/files for different OCDS versions. This just means the same endpoint/file shouldn't mix versions.)

[jpmckinney]

I'm not clear on the distinction made by "general guidance", so I'll mention some specific guidance here.

From #866 (comment):

• While adopting "planning processes" is optional, we can describe what sorts of changes a publisher would have to make. There is, of course, the separation/re-mapping of a 1.1 process into a 1.2 contracting process and a 1.2 planning process. We should also check planning extensions for any unusual implications (e.g. cross-references from later stages or similar).

[jpmckinney]

Related #862

[duncandewhurst]

Noting that this issue is probably best addressed once we have finalised the other changes made in 1.2.