diff --git a/phpBB/adm/style/acp_ext_gallery.html b/phpBB/adm/style/acp_ext_gallery.html
index 9be59429f6..f9cdad34ff 100644
--- a/phpBB/adm/style/acp_ext_gallery.html
+++ b/phpBB/adm/style/acp_ext_gallery.html
@@ -45,7 +45,7 @@
 		<tr>
 			<td>
 				<strong>{{ extension.name }}</strong><br />
-				<span><a href="{{ extension.url }}">{{ lang('DETAILS') }}</a> &bull; <a href="">{{ lang('INSTALL') }}</a></span>
+				<span><a href="{{ extension.url }}">{{ lang('DETAILS') }}</a> &bull; <a href="{{ U_ACTION }}&amp;action=install&amp;extension={{ extension.composer_name|url_encode }}">{{ lang('INSTALL') }}</a></span>
 			</td>
 			<td>{{ extension.version }}</td>
 			<td>{{ extension.description }}</td>
diff --git a/phpBB/ext/index.htm b/phpBB/ext/index.htm
old mode 100644
new mode 100755
diff --git a/phpBB/includes/acp/acp_extensions.php b/phpBB/includes/acp/acp_extensions.php
index 01e0b5e245..9506a168a4 100644
--- a/phpBB/includes/acp/acp_extensions.php
+++ b/phpBB/includes/acp/acp_extensions.php
@@ -405,14 +405,56 @@ class acp_extensions
 	{
 		global $phpbb_container;
 
-		/** @var \phpbb\composer\extension_manager $manager */
-		$manager = $phpbb_container->get('ext.composer.manager');
-		$this->page_title = 'ACP_EXTENSIONS_GALLERY';
-		$this->tpl_name = 'acp_ext_gallery';
+		$action = $this->request->variable('action', 'list');
 
-		$this->request->enable_super_globals();
-		$this->template->assign_var('extensions', $manager->get_available_packages());
-		$this->request->disable_super_globals();
+		/** @var \phpbb\language\language $language */
+		$language = $phpbb_container->get('language');
+
+		/** @var \phpbb\composer\manager $composer_manager */
+		$composer_manager = $phpbb_container->get('ext.composer.manager');
+
+		switch ($action)
+		{
+			case 'install':
+				$extension = $this->request->variable('extension', '');
+
+				if (empty($extension))
+				{
+					redirect($this->u_action);
+				}
+
+				$formatter = new \Composer\Console\HtmlOutputFormatter([
+					'warning' => new \Symfony\Component\Console\Formatter\OutputFormatterStyle('black', 'yellow')
+				]);
+
+				$composer_io = new \phpbb\composer\io\web_io($language, '', \Symfony\Component\Console\Output\OutputInterface::VERBOSITY_NORMAL, $formatter);
+
+				try
+				{
+					$composer_manager->install((array) $extension, $composer_io);
+				}
+				catch (\phpbb\exception\runtime_exception $e)
+				{
+					trigger_error($language->lang_array($e->getMessage(), $e->get_parameters()) . '<br /><br />' . $composer_io->getOutput() . adm_back_link($this->u_action), E_USER_WARNING);
+				}
+
+				trigger_error($language->lang('EXTENSIONS_INSTALLED') . '<br /><br />' . $composer_io->getOutput() . adm_back_link($this->u_action));
+
+				break;
+			case 'remove':
+				break;
+			case 'list':
+			default:
+				/** @var \phpbb\composer\extension_manager $manager */
+				$manager = $phpbb_container->get('ext.composer.manager');
+				$this->page_title = 'ACP_EXTENSIONS_GALLERY';
+				$this->tpl_name = 'acp_ext_gallery';
+
+				$this->request->enable_super_globals();
+				$this->template->assign_var('extensions', $manager->get_available_packages());
+				$this->request->disable_super_globals();
+				break;
+		}
 	}
 
 	/**
diff --git a/phpBB/phpbb/composer/installer.php b/phpBB/phpbb/composer/installer.php
index 1135e13c8e..442dcc3f43 100644
--- a/phpBB/phpbb/composer/installer.php
+++ b/phpBB/phpbb/composer/installer.php
@@ -119,7 +119,7 @@ class installer
 			->setDumpAutoloader(false)
 			->setPreferStable(true)
 			->setRunScripts(false)
-			->setDryRun(false);
+			->setDryRun(true);
 
 		try
 		{
@@ -282,6 +282,7 @@ class installer
 				// Generates the entry
 				$available[$name] = [];
 				$available[$name]['name'] = $highest_version->getPrettyName();
+				$available[$name]['composer_name'] = $highest_version->getName();
 				$available[$name]['version'] = $highest_version->getPrettyVersion();
 
 				if ($version instanceof CompletePackage)
diff --git a/phpBB/phpbb/composer/io/console_io.php b/phpBB/phpbb/composer/io/console_io.php
index 33ac77ba4e..14c1ef29e9 100644
--- a/phpBB/phpbb/composer/io/console_io.php
+++ b/phpBB/phpbb/composer/io/console_io.php
@@ -29,6 +29,7 @@ class console_io extends ConsoleIO
 	 * @param InputInterface	$input		The input instance
 	 * @param OutputInterface	$output		The output instance
 	 * @param HelperSet			$helperSet	The helperSet instance
+	 * @param language			$language	Language object
 	 */
 	public function __construct(InputInterface $input, OutputInterface $output, HelperSet $helperSet, language $language)
 	{
diff --git a/phpBB/phpbb/composer/io/web_io.php b/phpBB/phpbb/composer/io/web_io.php
index 9e8aa6ec76..e7927c7233 100644
--- a/phpBB/phpbb/composer/io/web_io.php
+++ b/phpBB/phpbb/composer/io/web_io.php
@@ -15,25 +15,23 @@ namespace phpbb\composer\io;
 
 use Composer\IO\BufferIO;
 use phpbb\language\language;
-use Symfony\Component\Console\Helper\HelperSet;
-use Symfony\Component\Console\Input\InputInterface;
-use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Formatter\OutputFormatterInterface;
+use Symfony\Component\Console\Output\StreamOutput;
 
 class web_io extends BufferIO
 {
 	use translate_composer_trait;
 
 	/**
-	 * Constructor.
-	 *
-	 * @param InputInterface	$input		The input instance
-	 * @param OutputInterface	$output		The output instance
-	 * @param HelperSet			$helperSet	The helperSet instance
+	 * @param language					$language	Language object
+	 * @param string					$input		Input string
+	 * @param int						$verbosity	Verbosity level
+	 * @param OutputFormatterInterface	$formatter	Output formatter
 	 */
-	public function __construct(InputInterface $input, OutputInterface $output, HelperSet $helperSet, language $language)
+	public function __construct(language $language, $input = '', $verbosity = StreamOutput::VERBOSITY_NORMAL, OutputFormatterInterface $formatter = null)
 	{
 		$this->language = $language;
 
-		parent::__construct($input, $output, $helperSet);
+		parent::__construct($input, $verbosity, $formatter);
 	}
 }