diff --git a/components/bower.json b/components/bower.json
index 77ea1a51e..9f8f5ec0f 100644
--- a/components/bower.json
+++ b/components/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "handlebars",
-  "version": "4.3.3",
+  "version": "4.3.4",
   "main": "handlebars.js",
   "license": "MIT",
   "dependencies": {}
diff --git a/components/handlebars.js.nuspec b/components/handlebars.js.nuspec
index 0da828312..eb693b3cf 100644
--- a/components/handlebars.js.nuspec
+++ b/components/handlebars.js.nuspec
@@ -2,7 +2,7 @@
 <package>
 	<metadata>
 		<id>handlebars.js</id>
-		<version>4.3.3</version>
+		<version>4.3.4</version>
 		<authors>handlebars.js Authors</authors>
 		<licenseUrl>https://github.com/wycats/handlebars.js/blob/master/LICENSE</licenseUrl>
 		<projectUrl>https://github.com/wycats/handlebars.js/</projectUrl>
diff --git a/components/package.json b/components/package.json
index 3b544d7a5..11d5e3b70 100644
--- a/components/package.json
+++ b/components/package.json
@@ -1,6 +1,6 @@
 {
   "name": "handlebars",
-  "version": "4.3.3",
+  "version": "4.3.4",
   "license": "MIT",
   "jspm": {
     "main": "handlebars",
diff --git a/lib/handlebars/base.js b/lib/handlebars/base.js
index c047af8de..312090345 100644
--- a/lib/handlebars/base.js
+++ b/lib/handlebars/base.js
@@ -4,7 +4,7 @@ import {registerDefaultHelpers} from './helpers';
 import {registerDefaultDecorators} from './decorators';
 import logger from './logger';
 
-export const VERSION = '4.3.3';
+export const VERSION = '4.3.4';
 export const COMPILER_REVISION = 8;
 export const LAST_COMPATIBLE_COMPILER_REVISION = 7;
 
diff --git a/lib/handlebars/compiler/javascript-compiler.js b/lib/handlebars/compiler/javascript-compiler.js
index 3491aad8e..dec107e8b 100644
--- a/lib/handlebars/compiler/javascript-compiler.js
+++ b/lib/handlebars/compiler/javascript-compiler.js
@@ -13,15 +13,13 @@ JavaScriptCompiler.prototype = {
   // PUBLIC API: You can override these methods in a subclass to provide
   // alternative compiled forms for name lookup and buffering semantics
   nameLookup: function(parent, name/* , type*/) {
+    const isEnumerable = [ this.aliasable('container.propertyIsEnumerable'), '.call(', parent, ',"constructor")'];
+
     if (name === 'constructor') {
-      return ['(', _isEnumerable(), '?', _actualLookup(), ' : undefined)'];
+      return ['(', isEnumerable, '?', _actualLookup(), ' : undefined)'];
     }
     return _actualLookup();
 
-    function _isEnumerable() {
-      return `Object.prototype.propertyIsEnumerable.call(${parent},'constructor')`;
-    }
-
     function _actualLookup() {
       if (JavaScriptCompiler.isValidJavaScriptVariableName(name)) {
         return [parent, '.', name];
@@ -222,7 +220,6 @@ JavaScriptCompiler.prototype = {
     let aliasCount = 0;
     for (let alias in this.aliases) { // eslint-disable-line guard-for-in
       let node = this.aliases[alias];
-
       if (this.aliases.hasOwnProperty(alias) && node.children && node.referenceCount > 1) {
         varDeclarations += ', alias' + (++aliasCount) + '=' + alias;
         node.children[0] = 'alias' + aliasCount;
diff --git a/package.json b/package.json
index 5c115c307..788600ce8 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "handlebars",
   "barename": "handlebars",
-  "version": "4.3.3",
+  "version": "4.3.4",
   "description": "Handlebars provides the power necessary to let you build semantic templates effectively with no frustration",
   "homepage": "http://www.handlebarsjs.com/",
   "keywords": [
diff --git a/release-notes.md b/release-notes.md
index 1f8da4a70..dec4f9861 100644
--- a/release-notes.md
+++ b/release-notes.md
@@ -2,7 +2,15 @@
 
 ## Development
 
-[Commits](https://github.com/wycats/handlebars.js/compare/v4.3.3...master)
+[Commits](https://github.com/wycats/handlebars.js/compare/v4.3.4...master)
+
+## v4.3.4 - September 28th, 2019
+- fix: harden "propertyIsEnumerable"-check - ff4d827
+
+Compatibility notes:
+- No incompatibilities are known.
+
+[Commits](https://github.com/wycats/handlebars.js/compare/v4.3.3...v4.3.4)
 
 ## v4.3.3 - September 27th, 2019
  - fix test case for browsers that do not support __defineGetter__ - 8742bde