diff --git a/client/rechallenge/transformers.js b/client/rechallenge/transformers.js
index bb9938a01e..ab578f7ec9 100644
--- a/client/rechallenge/transformers.js
+++ b/client/rechallenge/transformers.js
@@ -25,7 +25,7 @@ const transformersForHtmlJS = {
       name: 'add-loop-protect',
       transformer: function addLoopProtect(file) {
         const _contents = file.contents.toLowerCase();
-        if (file.ext === 'html' && !_contents.includes('<script>')) {
+        if (file.ext === 'html' && _contents.indexOf('<script>') === -1) {
           // No JavaScript in user code, so no need for loopProtect
           return updateContents(file.contents, file);
         }
diff --git a/common/app/utils/blockNameify.js b/common/app/utils/blockNameify.js
index f12fbbd790..c431f7a33b 100644
--- a/common/app/utils/blockNameify.js
+++ b/common/app/utils/blockNameify.js
@@ -28,7 +28,7 @@ export default function blockNameify(phrase) {
   }
   return phrase.split('-')
     .map((word) => {
-      if (noFormatting.includes(word)) {
+      if (noFormatting.indexOf(word) !== -1) {
         return word;
       }
       if (word === 'javascript') {
diff --git a/seed/challenges/02-javascript-algorithms-and-data-structures/object-oriented-programming.json b/seed/challenges/02-javascript-algorithms-and-data-structures/object-oriented-programming.json
index a2e7ac3309..00126a9586 100644
--- a/seed/challenges/02-javascript-algorithms-and-data-structures/object-oriented-programming.json
+++ b/seed/challenges/02-javascript-algorithms-and-data-structures/object-oriented-programming.json
@@ -334,7 +334,7 @@
         ""
       ],
       "tests": [
-        "assert(ownProps.includes('name') && ownProps.includes('numLegs'), 'message: <code>ownProps</code> should include the values <code>\"numLegs\"</code> and <code>\"name\"</code>.');",
+        "assert(ownProps.indexOf('name') !== -1 && ownProps.indexOf('numLegs') !== -1, 'message: <code>ownProps</code> should include the values <code>\"numLegs\"</code> and <code>\"name\"</code>.');",
         "assert(!/\\Object.keys/.test(code), 'message: Solve this challenge without using the built in method <code>Object.keys()</code>.');"
       ],
       "solutions": [
@@ -414,8 +414,8 @@
         ""
       ],
       "tests": [
-        "assert(ownProps.includes('name'), 'message: The <code>ownProps</code> array should include <code>\"name\"</code>.');",
-        "assert(prototypeProps.includes('numLegs'), 'message: The <code>prototypeProps</code> array should include <code>\"numLegs\"</code>.');",
+        "assert(ownProps.indexOf('name') !== -1, 'message: The <code>ownProps</code> array should include <code>\"name\"</code>.');",
+        "assert(prototypeProps.indexOf('numLegs') !== -1, 'message: The <code>prototypeProps</code> array should include <code>\"numLegs\"</code>.');",
         "assert(!/\\Object.keys/.test(code), 'message: Solve this challenge without using the built in method <code>Object.keys()</code>.');"
       ],
       "solutions": [
diff --git a/seed/challenges/08-coding-interview-questions-and-take-home-assignments/coding-interview-data-structure-questions.json b/seed/challenges/08-coding-interview-questions-and-take-home-assignments/coding-interview-data-structure-questions.json
index 244de77b4d..faf6eb9a81 100644
--- a/seed/challenges/08-coding-interview-questions-and-take-home-assignments/coding-interview-data-structure-questions.json
+++ b/seed/challenges/08-coding-interview-questions-and-take-home-assignments/coding-interview-data-structure-questions.json
@@ -2579,9 +2579,9 @@
       ],
       "tests": [
         "assert(Object.keys(undirectedAdjList).length === 4, 'message: <code>undirectedAdjList</code> should only contain four nodes.');",
-        "assert(undirectedAdjList.James.includes(\"Jeff\") && undirectedAdjList.Jeff.includes(\"James\"), 'message: There should be an edge between <code>Jeff</code> and <code>James</code>.');",
-        "assert(undirectedAdjList.Jill.includes(\"Jenny\") && undirectedAdjList.Jill.includes(\"Jenny\"), 'message: There should be an edge between <code>Jill</code> and <code>Jenny</code>.');",
-        "assert(undirectedAdjList.Jeff.includes(\"Jenny\") && undirectedAdjList.Jenny.includes(\"Jeff\"), 'message: There should be an edge between <code>Jeff</code> and <code>Jenny</code>.');"
+        "assert(undirectedAdjList.James.indexOf(\"Jeff\") !== -1 && undirectedAdjList.Jeff.indexOf(\"James\") !== -1, 'message: There should be an edge between <code>Jeff</code> and <code>James</code>.');",
+        "assert(undirectedAdjList.Jill.indexOf(\"Jenny\") !== -1 && undirectedAdjList.Jill.indexOf(\"Jenny\") !== -1, 'message: There should be an edge between <code>Jill</code> and <code>Jenny</code>.');",
+        "assert(undirectedAdjList.Jeff.indexOf(\"Jenny\") !== -1 && undirectedAdjList.Jenny.indexOf(\"Jeff\") !== -1, 'message: There should be an edge between <code>Jeff</code> and <code>Jenny</code>.');"
       ],
       "type": "waypoint",
       "releasedOn": "Feb 17, 2017",