As announced on zotero-dev, version 2 of the Zotero Web API brings many changes to enable API-based syncing. While read-only clients may continue to work properly, clients that write to the API are likely to need updating.
This page provides a brief summary of changes and may not be comprehensive. See the appropriate documentation sections for full details on all changes.
relations property of item JSON. Currently, only the RDF predicates used by Zotero itself are available.If-Match has been replaced by If-Unmodified-Since-Version and JSON version properties.204 No Content, while multi-object writes return 200 OK with a JSON document indicating the status of each write.X-Zotero-Write-Token has changed to Zotero-Write-Token.note or attachment properties when creating top-level items or by POSTing to <userOrGroupPrefix>/items/<itemKey>/children. Instead, child items can be created or moved by including a parentItem property in the item's JSON.collections object, similar to the items object used for items. parent property for collections has been changed to parentCollection.collections property. The previous POST and DELETE requests have been removed.