I have received some crash reports from nexus 5.0 devices after the update to Android 5.0 and releasing code compiled against the latest API 21.
Caused by: java.lang.IllegalArgumentException: Service Intent must be explicit: Intent { act=com.dsi.ant.bind.AntService }
at android.app.ContextImpl.validateServiceIntent(ContextImpl.java:1674)
at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1773)
at android.app.ContextImpl.bindService(ContextImpl.java:1751)
at android.content.ContextWrapper.bindService(ContextWrapper.java:538)
at com.dsi.ant.a.a(SourceFile:200)
This is doing AntService.bindService(mContext, mAntRadioServiceConnection);
With earlier builds it's just a warning but Google have changed it to an exception with API 21 builds hence the crash. I will look at moving back an API version although that of course is not a long term solution.
I am not sure if the user has the ANT+ enabler app or some sort of Usb Host mode setup.