diff --git a/wp-content/themes/twentyseventeen/assets/js/html5.js b/wp-content/themes/twentyseventeen/assets/js/html5.js
index 65e246bb47..45ea723dd5 100644
--- a/wp-content/themes/twentyseventeen/assets/js/html5.js
+++ b/wp-content/themes/twentyseventeen/assets/js/html5.js
@@ -1 +1,326 @@
-// This theme does not support old versions of Microsoft Internet Explorer anymore.
+/**
+* @preserve HTML5 Shiv 3.7.3 | @afarkas @jdalton @jon_neal @rem | MIT/GPL2 Licensed
+*/
+;(function(window, document) {
+/*jshint evil:true */
+  /** version */
+  var version = '3.7.3';
+
+  /** Preset options */
+  var options = window.html5 || {};
+
+  /** Used to skip problem elements */
+  var reSkip = /^<|^(?:button|map|select|textarea|object|iframe|option|optgroup)$/i;
+
+  /** Not all elements can be cloned in IE **/
+  var saveClones = /^(?:a|b|code|div|fieldset|h1|h2|h3|h4|h5|h6|i|label|li|ol|p|q|span|strong|style|table|tbody|td|th|tr|ul)$/i;
+
+  /** Detect whether the browser supports default html5 styles */
+  var supportsHtml5Styles;
+
+  /** Name of the expando, to work with multiple documents or to re-shiv one document */
+  var expando = '_html5shiv';
+
+  /** The id for the the documents expando */
+  var expanID = 0;
+
+  /** Cached data for each document */
+  var expandoData = {};
+
+  /** Detect whether the browser supports unknown elements */
+  var supportsUnknownElements;
+
+  (function() {
+    try {
+        var a = document.createElement('a');
+        a.innerHTML = '<xyz></xyz>';
+        //if the hidden property is implemented we can assume, that the browser supports basic HTML5 Styles
+        supportsHtml5Styles = ('hidden' in a);
+
+        supportsUnknownElements = a.childNodes.length == 1 || (function() {
+          // assign a false positive if unable to shiv
+          (document.createElement)('a');
+          var frag = document.createDocumentFragment();
+          return (
+            typeof frag.cloneNode == 'undefined' ||
+            typeof frag.createDocumentFragment == 'undefined' ||
+            typeof frag.createElement == 'undefined'
+          );
+        }());
+    } catch(e) {
+      // assign a false positive if detection fails => unable to shiv
+      supportsHtml5Styles = true;
+      supportsUnknownElements = true;
+    }
+
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
+  /**
+   * Creates a style sheet with the given CSS text and adds it to the document.
+   * @private
+   * @param {Document} ownerDocument The document.
+   * @param {String} cssText The CSS text.
+   * @returns {StyleSheet} The style element.
+   */
+  function addStyleSheet(ownerDocument, cssText) {
+    var p = ownerDocument.createElement('p'),
+        parent = ownerDocument.getElementsByTagName('head')[0] || ownerDocument.documentElement;
+
+    p.innerHTML = 'x<style>' + cssText + '</style>';
+    return parent.insertBefore(p.lastChild, parent.firstChild);
+  }
+
+  /**
+   * Returns the value of `html5.elements` as an array.
+   * @private
+   * @returns {Array} An array of shived element node names.
+   */
+  function getElements() {
+    var elements = html5.elements;
+    return typeof elements == 'string' ? elements.split(' ') : elements;
+  }
+
+  /**
+   * Extends the built-in list of html5 elements
+   * @memberOf html5
+   * @param {String|Array} newElements whitespace separated list or array of new element names to shiv
+   * @param {Document} ownerDocument The context document.
+   */
+  function addElements(newElements, ownerDocument) {
+    var elements = html5.elements;
+    if(typeof elements != 'string'){
+      elements = elements.join(' ');
+    }
+    if(typeof newElements != 'string'){
+      newElements = newElements.join(' ');
+    }
+    html5.elements = elements +' '+ newElements;
+    shivDocument(ownerDocument);
+  }
+
+   /**
+   * Returns the data associated to the given document
+   * @private
+   * @param {Document} ownerDocument The document.
+   * @returns {Object} An object of data.
+   */
+  function getExpandoData(ownerDocument) {
+    var data = expandoData[ownerDocument[expando]];
+    if (!data) {
+        data = {};
+        expanID++;
+        ownerDocument[expando] = expanID;
+        expandoData[expanID] = data;
+    }
+    return data;
+  }
+
+  /**
+   * returns a shived element for the given nodeName and document
+   * @memberOf html5
+   * @param {String} nodeName name of the element
+   * @param {Document|DocumentFragment} ownerDocument The context document.
+   * @returns {Object} The shived element.
+   */
+  function createElement(nodeName, ownerDocument, data){
+    if (!ownerDocument) {
+        ownerDocument = document;
+    }
+    if(supportsUnknownElements){
+        return ownerDocument.createElement(nodeName);
+    }
+    if (!data) {
+        data = getExpandoData(ownerDocument);
+    }
+    var node;
+
+    if (data.cache[nodeName]) {
+        node = data.cache[nodeName].cloneNode();
+    } else if (saveClones.test(nodeName)) {
+        node = (data.cache[nodeName] = data.createElem(nodeName)).cloneNode();
+    } else {
+        node = data.createElem(nodeName);
+    }
+
+    // Avoid adding some elements to fragments in IE < 9 because
+    // * Attributes like `name` or `type` cannot be set/changed once an element
+    //   is inserted into a document/fragment
+    // * Link elements with `src` attributes that are inaccessible, as with
+    //   a 403 response, will cause the tab/window to crash
+    // * Script elements appended to fragments will execute when their `src`
+    //   or `text` property is set
+    return node.canHaveChildren && !reSkip.test(nodeName) && !node.tagUrn ? data.frag.appendChild(node) : node;
+  }
+
+  /**
+   * returns a shived DocumentFragment for the given document
+   * @memberOf html5
+   * @param {Document} ownerDocument The context document.
+   * @returns {Object} The shived DocumentFragment.
+   */
+  function createDocumentFragment(ownerDocument, data){
+    if (!ownerDocument) {
+        ownerDocument = document;
+    }
+    if(supportsUnknownElements){
+        return ownerDocument.createDocumentFragment();
+    }
+    data = data || getExpandoData(ownerDocument);
+    var clone = data.frag.cloneNode(),
+        i = 0,
+        elems = getElements(),
+        l = elems.length;
+    for(;i<l;i++){
+        clone.createElement(elems[i]);
+    }
+    return clone;
+  }
+
+  /**
+   * Shivs the `createElement` and `createDocumentFragment` methods of the document.
+   * @private
+   * @param {Document|DocumentFragment} ownerDocument The document.
+   * @param {Object} data of the document.
+   */
+  function shivMethods(ownerDocument, data) {
+    if (!data.cache) {
+        data.cache = {};
+        data.createElem = ownerDocument.createElement;
+        data.createFrag = ownerDocument.createDocumentFragment;
+        data.frag = data.createFrag();
+    }
+
+
+    ownerDocument.createElement = function(nodeName) {
+      //abort shiv
+      if (!html5.shivMethods) {
+          return data.createElem(nodeName);
+      }
+      return createElement(nodeName, ownerDocument, data);
+    };
+
+    ownerDocument.createDocumentFragment = Function('h,f', 'return function(){' +
+      'var n=f.cloneNode(),c=n.createElement;' +
+      'h.shivMethods&&(' +
+        // unroll the `createElement` calls
+        getElements().join().replace(/[\w\-:]+/g, function(nodeName) {
+          data.createElem(nodeName);
+          data.frag.createElement(nodeName);
+          return 'c("' + nodeName + '")';
+        }) +
+      ');return n}'
+    )(html5, data.frag);
+  }
+
+  /*--------------------------------------------------------------------------*/
+
+  /**
+   * Shivs the given document.
+   * @memberOf html5
+   * @param {Document} ownerDocument The document to shiv.
+   * @returns {Document} The shived document.
+   */
+  function shivDocument(ownerDocument) {
+    if (!ownerDocument) {
+        ownerDocument = document;
+    }
+    var data = getExpandoData(ownerDocument);
+
+    if (html5.shivCSS && !supportsHtml5Styles && !data.hasCSS) {
+      data.hasCSS = !!addStyleSheet(ownerDocument,
+        // corrects block display not defined in IE6/7/8/9
+        'article,aside,dialog,figcaption,figure,footer,header,hgroup,main,nav,section{display:block}' +
+        // adds styling not present in IE6/7/8/9
+        'mark{background:#FF0;color:#000}' +
+        // hides non-rendered elements
+        'template{display:none}'
+      );
+    }
+    if (!supportsUnknownElements) {
+      shivMethods(ownerDocument, data);
+    }
+    return ownerDocument;
+  }
+
+  /*--------------------------------------------------------------------------*/
+
+  /**
+   * The `html5` object is exposed so that more elements can be shived and
+   * existing shiving can be detected on iframes.
+   * @type Object
+   * @example
+   *
+   * // options can be changed before the script is included
+   * html5 = { 'elements': 'mark section', 'shivCSS': false, 'shivMethods': false };
+   */
+  var html5 = {
+
+    /**
+     * An array or space separated string of node names of the elements to shiv.
+     * @memberOf html5
+     * @type Array|String
+     */
+    'elements': options.elements || 'abbr article aside audio bdi canvas data datalist details dialog figcaption figure footer header hgroup main mark meter nav output picture progress section summary template time video',
+
+    /**
+     * current version of html5shiv
+     */
+    'version': version,
+
+    /**
+     * A flag to indicate that the HTML5 style sheet should be inserted.
+     * @memberOf html5
+     * @type Boolean
+     */
+    'shivCSS': (options.shivCSS !== false),
+
+    /**
+     * Is equal to true if a browser supports creating unknown/HTML5 elements
+     * @memberOf html5
+     * @type boolean
+     */
+    'supportsUnknownElements': supportsUnknownElements,
+
+    /**
+     * A flag to indicate that the document's `createElement` and `createDocumentFragment`
+     * methods should be overwritten.
+     * @memberOf html5
+     * @type Boolean
+     */
+    'shivMethods': (options.shivMethods !== false),
+
+    /**
+     * A string to describe the type of `html5` object ("default" or "default print").
+     * @memberOf html5
+     * @type String
+     */
+    'type': 'default',
+
+    // shivs the document according to the specified `html5` object options
+    'shivDocument': shivDocument,
+
+    //creates a shived element
+    createElement: createElement,
+
+    //creates a shived documentFragment
+    createDocumentFragment: createDocumentFragment,
+
+    //extends list of elements
+    addElements: addElements
+  };
+
+  /*--------------------------------------------------------------------------*/
+
+  // expose html5
+  window.html5 = html5;
+
+  // shiv the document
+  shivDocument(document);
+
+  if(typeof module == 'object' && module.exports){
+    module.exports = html5;
+  }
+
+}(typeof window !== "undefined" ? window : this, document));
diff --git a/wp-content/themes/twentyseventeen/readme.txt b/wp-content/themes/twentyseventeen/readme.txt
index 34aadb8589..043e25bb52 100644
--- a/wp-content/themes/twentyseventeen/readme.txt
+++ b/wp-content/themes/twentyseventeen/readme.txt
@@ -37,6 +37,10 @@ GNU General Public License for more details.
 
 Twenty Seventeen bundles the following third-party resources:
 
+HTML5 Shiv, Copyright 2014 Alexander Farkas
+Licenses: MIT/GPL2
+Source: https://github.com/aFarkas/html5shiv
+
 jQuery scrollTo, Copyright 2007-2015 Ariel Flesler
 License: MIT
 Source: https://github.com/flesler/jquery.scrollTo
diff --git a/wp-includes/version.php b/wp-includes/version.php
index d6917c0e09..5757d40b85 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.3-beta3-56148';
+$wp_version = '6.3-beta3-56149';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.