I was given a Vodafone TrackiSafe tracker TRKM014TS model. The packaging says you need to download the "V By Vodafone" app.
Fruitless searching the web and Google Play suggest this no longer exists. The VF website says use "Vodafone Smart" app, though that only mentions working with Curve and Neo. As usual with VF, support pages abandon products soon after they stop selling them.
There is a "TrackiSafe" app, without any VF branding (which gets better ratings than Vodafone Smart app. Not difficult).