diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index f9a2ea85..00ebe74f 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -573,9 +573,8 @@ private function createCachePluginNode()
                         ->end()
                     ->end()
                 ->end()
-                ->enumNode('respect_cache_headers')
+                ->scalarNode('respect_cache_headers')
                     ->info('Whether we should care about cache headers or not [DEPRECATED]')
-                    ->values([null, true, false])
                     ->beforeNormalization()
                         ->always(function ($v) {
                             @trigger_error('The option "respect_cache_headers" is deprecated since version 1.3 and will be removed in 2.0. Use "respect_response_cache_directives" instead.', E_USER_DEPRECATED);
@@ -583,6 +582,10 @@ private function createCachePluginNode()
                             return $v;
                         })
                     ->end()
+                    ->validate()
+                        ->ifNotInArray([null, true, false])
+                        ->thenInvalid('Value for "respect_cache_headers" must be null or boolean')
+                    ->end()
                 ->end()
                 ->variableNode('respect_response_cache_directives')
                     ->info('A list of cache directives to respect when caching responses')
diff --git a/Tests/Resources/Fixtures/config/bc/issue-166.yml b/Tests/Resources/Fixtures/config/bc/issue-166.yml
new file mode 100644
index 00000000..ca9d0dff
--- /dev/null
+++ b/Tests/Resources/Fixtures/config/bc/issue-166.yml
@@ -0,0 +1,6 @@
+httplug:
+    plugins:
+        cache:
+            cache_pool: my_cache_pool
+            config:
+                respect_cache_headers: false
diff --git a/Tests/Unit/DependencyInjection/ConfigurationTest.php b/Tests/Unit/DependencyInjection/ConfigurationTest.php
index a5e5758b..0978cb8d 100644
--- a/Tests/Unit/DependencyInjection/ConfigurationTest.php
+++ b/Tests/Unit/DependencyInjection/ConfigurationTest.php
@@ -328,6 +328,24 @@ public function testCacheConfigDeprecationCompatibility()
         $this->assertProcessedConfigurationEquals($config, [$file]);
     }
 
+    /**
+     * @group legacy
+     */
+    public function testCacheConfigDeprecationCompatibilityIssue166()
+    {
+        $file = __DIR__.'/../../Resources/Fixtures/config/bc/issue-166.yml';
+        $config = $this->emptyConfig;
+        $config['plugins']['cache'] = array_merge($config['plugins']['cache'], [
+            'enabled' => true,
+            'cache_pool' => 'my_cache_pool',
+            'config' => [
+                'methods' => ['GET', 'HEAD'],
+                'respect_cache_headers' => false,
+            ],
+        ]);
+        $this->assertProcessedConfigurationEquals($config, [$file]);
+    }
+
     /**
      * @expectedException \Symfony\Component\Config\Definition\Exception\InvalidConfigurationException
      * @expectedExceptionMessage Can't configure both "toolbar" and "profiling" section. The "toolbar" config is deprecated as of version 1.3.0, please only use "profiling".