Google Maps JavaScript API stopped working

Question

Working at a CAD software company, clients can use google maps in their programs in an embedded browser, where they can zoom to a place, then get the elevations and build terrains in their programs. For this we use the same, untouched code for 2 or 3 years now. We got a report, that nothing is working anymore. Don't exactly know the date, when it has gone wrong. For example in the code we use this functionality:

function askForLocation(lat, lng, zoom) {
  initWithCoordinates(lat, lng, {
    movableMarker: true,
    addControls: true,
    zoomLevel: zoom,
    init: function() {
      google.maps.event.addListener(marker, 'position_changed', function() {
        if (typeof bridge === 'undefined') {} else {
          var mp = marker.getPosition();
          alert(mp.lat());
          bridge.setMarkerPosition(mp.lat(), mp.lng());
        }
      });
    }
  });
}

None of our other calls are working, for example:

var elevator = new google.maps.ElevationService(); elevator.getElevationForLocations(positionRequest, function(results, status) {
              if (status == google.maps.ElevationStatus.OK) {
              ...

My browser gives a warning when loading this HTML file:

Google Maps API warning: NoApiKeys https://developers.google.com/maps/documentation/javascript/error-messages#no-api-keys

Can you confirm, that let's suppose, since december, it's not possible to use maps api without apikey? We only used this call before:
scriptt src="http://maps.google.com/maps/api/js?libraries=places"

Is it possible, that due to a strict policy, that was changed in january/december we have to change our code?

Thank you in advance

Edit:

I saw this article, but it's not the case for me, because my googlemaps screen shows, I can move around, zoom, but can't get elevations, or can't search for locations: Whats the API Key for in Google Maps API V3? This article says the google maps screen is not loading.