Wait, is it nearly June 2017 already?
As per this notice on the Dropbox Developer Blog, the Dropbox API that WikiPack uses to sync pages will be turned off on June 1 2017.
As of this moment, WikiPack has not been updated to use the new API, which means that Dropbox sync will stop working at that time.
Unless I'm able to re-write the app, update it to use V2 of the API and deploy it over the weekend...