Hey folks :)
Are you a tool author relying on dumps or Special:Export or use Lua on Wikidata to access data in items? Please read on. The JSON format returned by the API and what we use to store the data internally has been different for a long time. This has been a headache as people had to deal with two different JSON serializations. We've fixed this now to only use one. This means the format you get in the XML dumps, via Special:Export and when accessing the raw item page content via Lua will change to be the same as what you get from the API. We plan to deploy this change on August 26th.
This is one of the remaining blockers for statements on properties and further progress on Commons support.
I'm sorry for the disruption. If you need help with adapting your tools please let me know.
Cheers Lydia