We are very sorry - but noticed a couple of hours ago that our latest update from yesterday (version 3.1 form December 13th) got corrupted on Google play and did not work.
We have posted an update (version 3.2) on Google Play. If you can not see that version yet you also can upload the update directly from our servers by typing:
www.trainchinese.com/android/download.php
into the browser of your phone.
Sorry again for this inconvenience!