In order to support new functionality for the pull to refresh feature, the nightlies have a breaking change.
If you are using pull to refresh, you must change your code.
Old :
<ion-content on-refresh="onRefresh()"
on-refresh-opening="onRefreshOpening()">
<ion-refresher></ion-refresher>
</ion-content>
New:
<ion-content>
<ion-refresher on-refresh="onRefresh()"
on-pulling="onRefreshOpening()">
</ion-refresher>
</ion-content>
Here is a working sample: http://codepen.io/ionic/pen/mqolp