Hi, Fundraising would like the ability to snapshot or retrieve a CentralNotice banner exactly as it was rendered at an earlier time, including the old revisions of templates, which is tricky and AFAICT not supported by MediaWiki-core.
I know this issue has come up before but it looks like development is external and has died out. The most relevant code seems to be Extension:BackwardsTimeTravel, which adds some expensive-looking hook callbacks, and Extension:Memento, which is too far into the future and amends how HTTP operates.
If ours is an unsupported usage, we'll have to implement a horrible kludge such as taking a recursive snapshot of all transcluded pages.
Thanks, Adam