In an article from Quartz today they have found that Android phones track your location even when location services is disabled and there is no SIM in the phone.  The information is gathered supposedly for messaging services, but it is also used for location based advertising.  Google has enabled this feature on the majority of newer versions of Android, though they did not say which ones.  Google claims that this will be turned off by the end of November 2017, it did not say if this required an update or would just happen automatically. See the linked article above for more details.