WhatsApp Keeps Crashing

We are running WhatsApp on a Lenovo IdeaTab, which according to Play Store, is not compatible with the device. Instead we installed it through the APK file. We have just created a fourth broadcast group, and now the app keeps crashing. 'WhatsApp is not responding". It is really frustrating. Is this to do with the version of the app or the device we are running it on?