diff --git a/phpBB/adm/index.php b/phpBB/adm/index.php
index f7343accef..519f6c8310 100644
--- a/phpBB/adm/index.php
+++ b/phpBB/adm/index.php
@@ -54,7 +54,13 @@ $module_id		= request_var('i', '');
 $mode			= request_var('mode', '');
 
 // Set custom style for admin area
-$template->set_custom_style('adm', $phpbb_admin_path . 'style');
+$template->set_custom_style(array(
+	array(
+		'name' 		=> 'adm',
+		'ext_path' 	=> 'adm/style/',
+	),
+), $phpbb_admin_path . 'style');
+
 $template->assign_var('T_ASSETS_PATH', $phpbb_root_path . 'assets');
 $template->assign_var('T_TEMPLATE_PATH', $phpbb_admin_path . 'style');
 
diff --git a/phpBB/adm/style/acp_groups.html b/phpBB/adm/style/acp_groups.html
index cf189f979f..f9846ea7cd 100644
--- a/phpBB/adm/style/acp_groups.html
+++ b/phpBB/adm/style/acp_groups.html
@@ -56,6 +56,7 @@
 
 	<fieldset>
 		<legend>{L_GROUP_OPTIONS_SAVE}</legend>
+	<!-- EVENT acp_group_options_before -->
 	<!-- IF S_USER_FOUNDER -->
 	<dl>
 		<dt><label for="group_founder_manage">{L_GROUP_FOUNDER_MANAGE}{L_COLON}</label><br /><span>{L_GROUP_FOUNDER_MANAGE_EXPLAIN}</span></dt>
@@ -78,6 +79,7 @@
 		<dt><label for="group_receive_pm">{L_GROUP_RECEIVE_PM}{L_COLON}</label><br /><span>{L_GROUP_RECEIVE_PM_EXPLAIN}</span></dt>
 		<dd><input name="group_receive_pm" type="checkbox" value="1" class="radio" id="group_receive_pm"{GROUP_RECEIVE_PM} /></dd>
 	</dl>
+	<!-- EVENT acp_group_options_after -->
 	</fieldset>
 
 	<fieldset>
diff --git a/phpBB/docs/events.md b/phpBB/docs/events.md
index 4a6a1895dd..4dc55540f3 100644
--- a/phpBB/docs/events.md
+++ b/phpBB/docs/events.md
@@ -22,6 +22,18 @@ acp_forums_normal_settings_append
 * Since: 3.1.0-a1
 * Purpose: Add settings to forums
 
+acp_group_options_before
+===
+* Location: adm/style/acp_groups.html
+* Since: 3.1.0-b4
+* Purpose: Add addtional options to group settings (before GROUP_FOUNDER_MANAGE)
+
+acp_group_options_after
+===
+* Location: adm/style/acp_groups.html
+* Since: 3.1.0-b4
+* Purpose: Add addtional options to group settings (after GROUP_RECEIVE_PM)
+
 acp_main_actions_append
 ===
 * Location: adm/style/acp_main.html
diff --git a/phpBB/includes/functions_messenger.php b/phpBB/includes/functions_messenger.php
index d170a689b6..3657a89aa0 100644
--- a/phpBB/includes/functions_messenger.php
+++ b/phpBB/includes/functions_messenger.php
@@ -255,7 +255,12 @@ class messenger
 			}
 		}
 
-		$this->set_template_paths($template_lang . '_email', $template_paths);
+		$this->set_template_paths(array(
+			array(
+				'name' 		=> $template_lang . '_email',
+				'ext_path' 	=> 'language/' . $template_lang . '/email'
+			),
+		), $template_paths);
 
 		$this->template->set_filenames(array(
 			'body'		=> $template_file . '.txt',
diff --git a/phpBB/includes/functions_module.php b/phpBB/includes/functions_module.php
index 5d456e6355..51284af233 100644
--- a/phpBB/includes/functions_module.php
+++ b/phpBB/includes/functions_module.php
@@ -584,7 +584,12 @@ class p_master
 
 				if (is_dir($module_style_dir))
 				{
-					$template->set_custom_style('adm', array($module_style_dir, $phpbb_admin_path . 'style'));
+					$template->set_custom_style(array(
+						array(
+							'name' 		=> 'adm',
+							'ext_path' 	=> 'adm/style/',
+						),
+					), array($module_style_dir, $phpbb_admin_path . 'style'));
 				}
 			}
 
diff --git a/phpBB/install/index.php b/phpBB/install/index.php
index e683324bdf..43970029cb 100644
--- a/phpBB/install/index.php
+++ b/phpBB/install/index.php
@@ -254,7 +254,12 @@ $phpbb_path_helper = $phpbb_container->get('path_helper');
 $template = new \phpbb\template\twig\twig($phpbb_path_helper, $config, $user, new \phpbb\template\context());
 $paths = array($phpbb_root_path . 'install/update/new/adm/style', $phpbb_admin_path . 'style');
 $paths = array_filter($paths, 'is_dir');
-$template->set_custom_style('adm', $paths);
+$template->set_custom_style(array(
+	array(
+		'name' 		=> 'adm',
+		'ext_path' 	=> 'adm/style/',
+	),
+), $paths);
 
 $path = array_shift($paths);
 
diff --git a/phpBB/install/install_update.php b/phpBB/install/install_update.php
index 1a90efc2b4..ab5fcc3f2b 100644
--- a/phpBB/install/install_update.php
+++ b/phpBB/install/install_update.php
@@ -145,7 +145,12 @@ class install_update extends module
 		// Set custom template again. ;)
 		$paths = array($phpbb_root_path . 'install/update/new/adm/style', $phpbb_admin_path . 'style');
 		$paths = array_filter($paths, 'is_dir');
-		$template->set_custom_style('adm', $paths);
+		$template->set_custom_style(array(
+			array(
+				'name' 		=> 'adm',
+				'ext_path' 	=> 'adm/style/',
+			),
+		), $paths);
 
 		$template->assign_vars(array(
 			'S_USER_LANG'			=> $user->lang['USER_LANG'],
diff --git a/phpBB/phpbb/template/twig/twig.php b/phpBB/phpbb/template/twig/twig.php
index 9d3b994ce6..bf27dd5f20 100644
--- a/phpBB/phpbb/template/twig/twig.php
+++ b/phpBB/phpbb/template/twig/twig.php
@@ -214,9 +214,13 @@ class twig extends \phpbb\template\base
 	*
 	* Note: Templates are still compiled to phpBB's cache directory.
 	*
-	* @param string|array $names Array of names or string of name of template(s) in inheritance tree order, used by extensions.
-	* @param string|array or string $paths Array of style paths, relative to current root directory
-	* @return phpbb_template $this
+	* @param string|array $names Array of names (or detailed names) or string of name of template(s) in inheritance tree order, used by extensions.
+	*	E.g. array(
+	*			'name' 		=> 'adm',
+	*			'ext_path' 	=> 'adm/style/',
+	*		)
+	* @param string|array of string $paths Array of style paths, relative to current root directory
+	* @return \phpbb\template\template $this
 	*/
 	public function set_custom_style($names, $paths)
 	{
@@ -237,10 +241,26 @@ class twig extends \phpbb\template\base
 				$namespace = str_replace('/', '_', $ext_namespace);
 				$paths = array();
 
-				foreach ($names as $style_name)
+				foreach ($names as $template_dir)
 				{
-					$ext_style_path = $ext_path . 'styles/' . $style_name . '/';
-					$ext_style_template_path = $ext_style_path . 'template/';
+					if (is_array($template_dir))
+					{
+						if (isset($template_dir['ext_path']))
+						{
+							$ext_style_template_path = $ext_path . $template_dir['ext_path'];
+							$ext_style_path = dirname($ext_style_template_path);
+						}
+						else
+						{
+							$ext_style_path = $ext_path . 'styles/' . $template_dir['name'] . '/';
+							$ext_style_template_path = $ext_style_path . 'template/';
+						}
+					}
+					else
+					{
+						$ext_style_path = $ext_path . 'styles/' . $template_dir . '/';
+						$ext_style_template_path = $ext_style_path . 'template/';
+					}
 
 					if (is_dir($ext_style_template_path))
 					{
diff --git a/phpBB/phpbb/version_helper.php b/phpBB/phpbb/version_helper.php
index 47e9bbe0f3..5991744e76 100644
--- a/phpBB/phpbb/version_helper.php
+++ b/phpBB/phpbb/version_helper.php
@@ -251,7 +251,7 @@ class version_helper
 
 			$info = json_decode($info, true);
 
-			if (empty($info['stable']) || empty($info['unstable']))
+			if (empty($info['stable']) && empty($info['unstable']))
 			{
 				$this->user->add_lang('acp/common');
 
@@ -267,6 +267,9 @@ class version_helper
 				}
 			}
 
+			$info['stable'] = (empty($info['stable'])) ? array() : $info['stable'];
+			$info['unstable'] = (empty($info['unstable'])) ? $info['stable'] : $info['unstable'];
+
 			$this->cache->put($cache_file, $info, 86400); // 24 hours
 		}
 
diff --git a/tests/version/version_test.php b/tests/version/version_test.php
index 142fd88636..bc4f2c0294 100644
--- a/tests/version/version_test.php
+++ b/tests/version/version_test.php
@@ -185,6 +185,11 @@ class phpbb_version_helper_test extends phpbb_test_case
 					),
 				),
 			),
+			array(
+				'1.1.0',
+				array(),
+				array(),
+			),
 		);
 	}
 
@@ -290,6 +295,11 @@ class phpbb_version_helper_test extends phpbb_test_case
 				),
 				'1.1.0-a2',
 			),
+			array(
+				'1.1.0',
+				array(),
+				null,
+			),
 		);
 	}