When checking out for disconnected editing, I was wondering if it is possible to download only the schema, not the underlying data? Some of our collector apps don't require the end user to see previously collected information at a site. It's not a big deal to download most related information unless it includes pictures. Then it can be overwhelming.
Try taking a look at the REST API for the JSON file. In "My Content" click on the feature layer you're interested in. When the page loads, you will find a link under "Layers" that will take you into the rest api. Near the top of rest api page is a link for "JSON". That may have what you need.
Thanks for the reply Randy. It looks like there are a number of Sync Capabilities identified there:
Does one of these allow me to download schema only? I don't think there is an interface for changing these and, if there was, would Collector honor those changes? Or does it expect certain properties set here?
There should be a section for "fields" in the file somewhere that would give you some of the info you seek.
You can use the REST API to update schema. Check out this blog: Updating Hosted Feature Services in ArcGIS Online. If you wish to do this, work with a copy of the feature for experimenting, make backups, etc. If you are using collector in offline mode, I would suggest that users sync all data, remove the map and reload it after successful changes made.