Update GLTFLoader error message for legacy file detection.

examples/js/loaders/GLTFLoader.js

@@ -106,7 +106,7 @@ THREE.GLTFLoader = ( function () {
 
 			if ( json.asset === undefined || json.asset.version[ 0 ] < 2 ) {
 
-				if ( onError ) onError( new Error( 'THREE.GLTFLoader: Unsupported asset. glTF versions >=2.0 are supported.' ) );
+				if ( onError ) onError( new Error( 'THREE.GLTFLoader: Unsupported asset. glTF versions >=2.0 are supported. Use LegacyGLTFLoader instead.' ) );
 				return;
 
 			}
@@ -421,7 +421,7 @@ THREE.GLTFLoader = ( function () {
 
 		} else if ( this.header.version < 2.0 ) {
 
-			throw new Error( 'THREE.GLTFLoader: Legacy binary file detected. Use GLTFLoader instead.' );
+			throw new Error( 'THREE.GLTFLoader: Legacy binary file detected. Use LegacyGLTFLoader instead.' );
 
 		}