Will LiveFleet mobile leave the existing BSM Vessel Tracker app defunct?

Eventually, yes.

LiveFleet mobile does not yet include the basic crew profile that is available in the BSM Vessel Tracker.

BSM Vessel Tracker app - Crew details

Once this feature is available in LiveFleet mobile, the BSM Vessel Tracker app will be redundant and will be discontinued. We will communicate this in advance and help existing users of the BSM Vessel Tracker app transition to LiveFleet mobile.