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Duolingo iOS app syncing bug

I finished four levels of course on my iPhone (online) when I was in the train. And for no reason, Duolingo app reset my progress back to previous level. It was the second time I saw this. The others may not be able to imagine how frustrating it would be. Because I am learning Duolingo English course for Chinese speakers, it is still in beta. It is very hard to level up.

Does anyone else have this issue? Or does it only happen in English course or only on my iPhone?

I think there is something wrong in Duolingo app's syncing logic. I have not hacked the app, I haven't looked at the IPA file or sniffed the traffic of the app. I am just guessing that the app is using Game Center to sync the performance/progress because it can sync offline data when iPhone comes back to online. But the problem is that Game Center is a system background service. It may not sync realtime. That may cause the syncing issue. On the other hand, it is quite easy to determinate which level is the lasted. When the app merge two different progresses. It should be able to determinate which one should be up-to-date. In my Activity page, I can see a level-up event. It means the app has the trace of the progress. But it just reset it for no reason.

I love Duolingo very much and hope it get better and better. Please fix this issue. Thanks.

May 8, 2014



I have trouble with my I pad going off in mid lesson. When it comes on again I am a the start against have done pres 1 over and over and I want to move on. How do I do this?


I made a lot of progress on the desktop browser site last night, but now none of it is showing up on the iPhone app. It does show up on the desktop version, however.

...and as I was typing this, I checked to see if a new update was available, because I had just updated to the newest version yesterday or the day before. Everything is synced! Try updating!


I have upgraded my app, hopefully, the issue will not happen again.

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