We plan to fix an inconsistency between the preview and delivery APIs which led to unability to resolve linked entries when fetching entries using locale=*.

When calling the https://preview.contentful.com/spaces/{spaceid}/entries/?locale=* endpoint, the locale property won't be present in the sys, just like when calling https://cdn.contentful.com/spaces/{spaceid}/entries/?locale=*.

While this is fixing an inconsistency, any program relying on having the locale property in the sys object on preview API calls using locale=* could break so we invite you to update these.