diff --git a/src/display/api.js b/src/display/api.js
index d761505da..3e74be324 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -1890,17 +1890,14 @@ var WorkerTransport = (function WorkerTransportClosure() {
         }
       }, this);
 
-      messageHandler.on('UnsupportedFeature',
-          function transportUnsupportedFeature(data) {
+      messageHandler.on('UnsupportedFeature', function(data) {
         if (this.destroyed) {
           return; // Ignore any pending requests if the worker was terminated.
         }
-        var featureId = data.featureId;
-        var loadingTask = this.loadingTask;
+        let loadingTask = this.loadingTask;
         if (loadingTask.onUnsupportedFeature) {
-          loadingTask.onUnsupportedFeature(featureId);
+          loadingTask.onUnsupportedFeature(data.featureId);
         }
-        _UnsupportedManager.notify(featureId);
       }, this);
 
       messageHandler.on('JpegDecode', function(data) {
@@ -2380,26 +2377,6 @@ var InternalRenderTask = (function InternalRenderTaskClosure() {
   return InternalRenderTask;
 })();
 
-/**
- * (Deprecated) Global observer of unsupported feature usages. Use
- * onUnsupportedFeature callback of the {PDFDocumentLoadingTask} instance.
- */
-var _UnsupportedManager = (function UnsupportedManagerClosure() {
-  var listeners = [];
-  return {
-    listen(cb) {
-      deprecated('Global UnsupportedManager.listen is used: ' +
-                 ' use PDFDocumentLoadingTask.onUnsupportedFeature instead');
-      listeners.push(cb);
-    },
-    notify(featureId) {
-      for (var i = 0, ii = listeners.length; i < ii; i++) {
-        listeners[i](featureId);
-      }
-    },
-  };
-})();
-
 var version, build;
 if (typeof PDFJSDev !== 'undefined') {
   version = PDFJSDev.eval('BUNDLE_VERSION');
@@ -2414,7 +2391,6 @@ export {
   PDFDocumentProxy,
   PDFPageProxy,
   setPDFNetworkStreamClass,
-  _UnsupportedManager,
   version,
   build,
 };
diff --git a/src/display/global.js b/src/display/global.js
index 926f3d393..1367fce3f 100644
--- a/src/display/global.js
+++ b/src/display/global.js
@@ -13,10 +13,6 @@
  * limitations under the License.
  */
 
-import {
-  _UnsupportedManager, getDocument, LoopbackPort, PDFDataRangeTransport,
-  PDFWorker
-} from './api';
 import {
   addLinkAttributes, CustomStyle, DEFAULT_LINK_REL, getFilenameFromUrl,
   isExternalLinkTargetSet, isValidUrl, LinkTarget
@@ -28,6 +24,9 @@ import {
   removeNullCharacters, setVerbosityLevel, shadow, UnexpectedResponseException,
   UnknownErrorException, UNSUPPORTED_FEATURES, Util, VERBOSITY_LEVELS, warn
 } from '../shared/util';
+import {
+  getDocument, LoopbackPort, PDFDataRangeTransport, PDFWorker
+} from './api';
 import { AnnotationLayer } from './annotation_layer';
 import globalScope from '../shared/global_scope';
 import { Metadata } from './metadata';
@@ -302,8 +301,6 @@ PDFJS.Metadata = Metadata;
 
 PDFJS.SVGGraphics = SVGGraphics;
 
-PDFJS.UnsupportedManager = _UnsupportedManager;
-
 export {
   globalScope,
   isWorker,