Hello, my game seems to be stuck at level 525, new levels don't show up?

I've been waiting patiently for weeks for new levels to come out. Finally, I searched the web to find the release date and people are talking about levels over 600. I tried updating my game at Google Play, it did need an update but doing so still did not give me any new levels. Any suggestions on how to fix this? I'm playing on Android OS, Google Nexus 10 tablet. Thanks.