We have released an updated version of our SDK for Windows Phone XAML based apps (both for WP7.x and WP8 apps). This update mitigates a rare NullReferenceException issue.
An important change is that we have combined SDKs for apps targeting Windows Phone 8 and Windows Phone 7.1 into one nuget package.
For apps targeting Windows Phone 8 nothing changes, but if you are working on a WP7 app you will need to remove the reference to the old (WP7) package and re-add it from the new package to get the updated version. All the future updates will come via this unified package. No code changes should be necessary. See documentation for the details on how to add this package to your Windows Phone project.