Best practice for schema change

We are trying to prepare our system for a schema change including a new required property, but it doesn’t work as expected.

We use this article as a reference:

According to this, we do the following:

  • extended all existing documents in the collection with the new property
  • extended the schema on Atlas UI with the new property, and hit save
  • just when we hit save, we encounter the following error (see image below)


Why do we get this warning/error?
What does it even mean, to be “sync-compatible”, is there any definition for this?

According to this image this shouldn’t be a breaking change:

Any help/hint would be greatly appreciated :slight_smile:

Hi, I think the issue here is just that lists / dictionaries / embedded objects in Device Sync are always optional. We can work on the messaging here a bit admittedly; however, I suspect it is just that you can / should define the list as optional.