Scheduled sync in offline apps?

In short: We want to rebuild an app that takes advantage of offline-possibilities, due to complaints of upload speed in some regions, as the app is used outside. It could be compared a little to package delivery people that “retrieve the delivery note", “take a picture”, “get a handsignature” and “Upload the confirmation”. Except of the Upload, those steps could be done offline. The synchronization function in nanoflows can provide the upload, but since the upload sometimes take up to 7 minutes, I do not want employees to wait. So I need to know how the upload can be done in the background? The best option would be a background scheduled event that frequently checks (or tries) to send the objects, but as far as I'm aware such thing does not exist? There should be some option to synchronize back with the server, without pressing a button. The employees cannot tell when they have a good signal and shouldn't be hold up for so long, either. What are the options for background syncing back to the server? 
1 answers

I stumbled upon this problem, too. I’m developing a Native application and I would keep the time of last synchronization, call a REST which would bring me back true or false. On the server side, I would retrieve the necessary objects and compare changedDate (or createdDate) attribute with the time of last sync. Return true if there is a new data, false for no new data. On client side for true full sync (or just the newest), for false try again later (maybe time event, scheduler, button action...). And don’t forget to change the time of last sync variable. If you have App events nanoflow action, that would be helpful.