how to use Estimote beacons on iOS 13?

Question

I can't make the func location manager work on iOS 13, it never gets called

           let nsuuid = NSUUID(uuidString: "B9407F30-F5F8-466E-AFF9-25556B57FE6D")
        if let clregion = nsuuid as UUID? {
            let constrain = CLBeaconIdentityConstraint(uuid: clregion)
            let region =  CLBeaconRegion(beaconIdentityConstraint: constrain, identifier: "Estimotes")
            self.locationManager.startRangingBeacons(satisfying: constrain)
        }
    }
// Beacon tracking function
    func locationManager(_ manager: CLLocationManager,
      didRange beacons: [CLBeacon],
    satisfying beaconConstraint: CLBeaconIdentityConstraint){
        //get an array of beacon that are close
        var knownBeacons = beacons.filter { ($0.proximity == CLProximity.immediate) && ($0.accuracy > 0) }

in iOS 12 I used to do like this,

let nsuuid = NSUUID(uuidString: "B9407F30-F5F8-466E-AFF9-25556B57FE6D")
        if let clregion = nsuuid as UUID? {
            let region = CLBeaconRegion(proximityUUID: clregion, identifier: "Estimotes")
            locationManager.startRangingBeacons(in: region)

        }
    }

// Beacon tracking function
    ffunc locationManager(_ manager: CLLocationManager, 
              didRangeBeacons beacons: [CLBeacon], 
                           in region: CLBeaconRegion){
        //get an array of beacon that are close
        var knownBeacons = beacons.filter { ($0.proximity == CLProximity.immediate) && ($0.accuracy > 0) }

and it worked just fine! Anyone can help me figure this ou, since the ios12 functions got deprecated