I left a bunch of small comments.
What do you think about linking to the doc in the migration guide and warnings? Would probably need to determine the URL based on the version.
Might also be helpful to mention that the intermediate_storage_defs argument on ModeDefinition is deprecated?
Nitpick: serve -> serves
Nitpick: output -> outputs
Nitpick: is -> are
the -> The
The word "feature" kind of makes it sound like object managers are a bell or whistle, when in fact they're the abstraction underlying all input/output loading/storing. Consider replacing with something like 'Loading inputs and storing outputs are now handled by "object managers", which can be configured via...'?
What do you think about linking to the doc in the migration guide and warnings?
Yes! I was planning to add the doc links once the related docs are released. will tag an issue to remind myself to do so