diff --git a/build/minify_pdfjs.sh b/build/minify_pdfjs.sh
index c4c8449a0..01c486f2e 100755
--- a/build/minify_pdfjs.sh
+++ b/build/minify_pdfjs.sh
@@ -11,8 +11,6 @@ java -jar build/closure-compiler-v20161201.jar --rewrite_polyfills false --langu
 java -jar build/closure-compiler-v20161201.jar --rewrite_polyfills false --language_out ECMASCRIPT5 --js src/third-party/doc/$DOC_STATIC_ASSETS_VERSION/pdf.worker.js --js_output_file src/third-party/doc/$DOC_STATIC_ASSETS_VERSION/pdf.worker.min.js
 
 java -jar build/closure-compiler-v20161201.jar --rewrite_polyfills false --language_out ECMASCRIPT5 --js src/third-party/doc/$DOC_STATIC_ASSETS_VERSION/pdf_viewer.js --js_output_file src/third-party/doc/$DOC_STATIC_ASSETS_VERSION/pdf_viewer.min.js
-
-java -jar build/closure-compiler-v20161201.jar --rewrite_polyfills false --language_out ECMASCRIPT5 --js src/third-party/doc/$DOC_STATIC_ASSETS_VERSION/compatibility.js --js_output_file src/third-party/doc/$DOC_STATIC_ASSETS_VERSION/compatibility.min.js
 echo "-----------------------------------------------------------------------------------"
 echo "Minifying pdf.js CSS with cssnano"
 echo "-----------------------------------------------------------------------------------"
diff --git a/build/upgrade_pdfjs.sh b/build/upgrade_pdfjs.sh
index 853342ea6..ff2884de8 100755
--- a/build/upgrade_pdfjs.sh
+++ b/build/upgrade_pdfjs.sh
@@ -16,7 +16,6 @@ git clone https://github.com/mozilla/pdfjs-dist.git
 
 echo "-----------------------------------------------------------------------------------"
 echo "Copying relevant files to Preview third-party dir..."
-echo "Note that we are NOT copying compatibility.js - that needs to be manually updated"
 echo "-----------------------------------------------------------------------------------"
 cp pdfjs-dist/build/pdf.js src/third-party/doc/$DOC_STATIC_ASSETS_VERSION/
 cp pdfjs-dist/build/pdf.worker.js src/third-party/doc/$DOC_STATIC_ASSETS_VERSION/
diff --git a/src/lib/viewers/doc/docAssets.js b/src/lib/viewers/doc/docAssets.js
index ad36f022e..b03586cd8 100644
--- a/src/lib/viewers/doc/docAssets.js
+++ b/src/lib/viewers/doc/docAssets.js
@@ -2,7 +2,6 @@ import { DOC_STATIC_ASSETS_VERSION } from '../../constants';
 
 const STATIC_URI = `third-party/doc/${DOC_STATIC_ASSETS_VERSION}/`;
 export const JS = [
-    `${STATIC_URI}compatibility.min.js`,
     `${STATIC_URI}pdf.min.js`,
     `${STATIC_URI}pdf_viewer.min.js`,
     `${STATIC_URI}pdf.worker.min.js`,
diff --git a/src/third-party/doc/0.118.0/compatibility.js b/src/third-party/doc/0.118.0/compatibility.js
deleted file mode 100644
index bf9bb8032..000000000
--- a/src/third-party/doc/0.118.0/compatibility.js
+++ /dev/null
@@ -1,105 +0,0 @@
-/* Copyright 2012 Mozilla Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-/* eslint strict: ["error", "function"] */
-/* eslint-disable no-extend-native */
-/* globals VBArray, PDFJS */
-
-(function compatibilityWrapper() {
-  'use strict';
-
-var userAgent = navigator.userAgent;
-
-var isAndroid = /Android/.test(userAgent);
-var isIE = userAgent.indexOf('Trident') >= 0;
-var isIOS = /\b(iPad|iPhone|iPod)(?=;)/.test(userAgent);
-var isSafari = /Safari\//.test(userAgent) &&
-               !/(Chrome\/|Android\s)/.test(userAgent);
-
-// Initializing PDFJS global object here, it case if we need to change/disable
-// some PDF.js features, e.g. range requests
-if (typeof PDFJS === 'undefined') {
-  (typeof window !== 'undefined' ? window : this).PDFJS = {};
-}
-
-// Checks if possible to use URL.createObjectURL()
-// Support: IE
-(function checkOnBlobSupport() {
-  // sometimes IE loosing the data created with createObjectURL(), see #3977
-  if (isIE) {
-    PDFJS.disableCreateObjectURL = true;
-  }
-})();
-
-// Checks if navigator.language is supported
-(function checkNavigatorLanguage() {
-  if ('language' in navigator) {
-    return;
-  }
-  PDFJS.locale = navigator.userLanguage || 'en-US';
-})();
-
-// Support: IE<10, Android<4.0, iOS
-(function checkRequestAnimationFrame() {
-  function fakeRequestAnimationFrame(callback) {
-    window.setTimeout(callback, 20);
-  }
-
-  if (isIOS) {
-    // requestAnimationFrame on iOS is broken, replacing with fake one.
-    window.requestAnimationFrame = fakeRequestAnimationFrame;
-    return;
-  }
-  if ('requestAnimationFrame' in window) {
-    return;
-  }
-  window.requestAnimationFrame =
-    window.mozRequestAnimationFrame ||
-    window.webkitRequestAnimationFrame ||
-    fakeRequestAnimationFrame;
-})();
-
-// Support: Android, iOS
-(function checkCanvasSizeLimitation() {
-  if (isIOS || isAndroid) {
-    // 5MP
-    PDFJS.maxCanvasPixels = 5242880;
-  }
-})();
-
-// Disable fullscreen support for certain problematic configurations.
-// Support: IE11+ (when embedded).
-(function checkFullscreenSupport() {
-  if (isIE && window.parent !== window) {
-    PDFJS.disableFullscreen = true;
-  }
-})();
-
-// Provides document.currentScript support
-// Support: IE, Chrome<29.
-(function checkCurrentScript() {
-  if ('currentScript' in document) {
-    return;
-  }
-  Object.defineProperty(document, 'currentScript', {
-    get: function () {
-      var scripts = document.getElementsByTagName('script');
-      return scripts[scripts.length - 1];
-    },
-    enumerable: true,
-    configurable: true
-  });
-})();
-
-}).call((typeof window === 'undefined') ? this : window);
\ No newline at end of file
diff --git a/src/third-party/doc/0.118.0/compatibility.min.js b/src/third-party/doc/0.118.0/compatibility.min.js
deleted file mode 100644
index 97b11c8e3..000000000
--- a/src/third-party/doc/0.118.0/compatibility.min.js
+++ /dev/null
@@ -1,2 +0,0 @@
-(function(){var a=navigator.userAgent,d=/Android/.test(a),b=0<=a.indexOf("Trident"),c=/\b(iPad|iPhone|iPod)(?=;)/.test(a);/Safari\//.test(a)&&/(Chrome\/|Android\s)/.test(a);"undefined"===typeof PDFJS&&(("undefined"!==typeof window?window:this).PDFJS={});b&&(PDFJS.disableCreateObjectURL=!0);"language"in navigator||(PDFJS.locale=navigator.userLanguage||"en-US");(function(){function a(a){window.setTimeout(a,20)}c?window.requestAnimationFrame=a:"requestAnimationFrame"in window||(window.requestAnimationFrame=
-window.mozRequestAnimationFrame||window.webkitRequestAnimationFrame||a)})();if(c||d)PDFJS.maxCanvasPixels=5242880;b&&window.parent!==window&&(PDFJS.disableFullscreen=!0);(function(){"currentScript"in document||Object.defineProperty(document,"currentScript",{get:function(){var a=document.getElementsByTagName("script");return a[a.length-1]},enumerable:!0,configurable:!0})})()}).call("undefined"===typeof window?this:window);