The new collector (Aurora) no longer supports location tracking. ESRI has promised a new app with better tracking. In the mean time we are using Workforce in the background, but it only works when connected.
The new functionality might be super but all my users are asking to see just their own breadcrumbs in Collector, not everyone else's, like they used to be able to do in ArcGIS Mobile for Windows.
In that app the breadcrumbs were visible to the user but were only synced up, never down from the server to the local map. It actually worked out really nicely for everyone.