diff --git a/mod/item.php b/mod/item.php
index 9326bf60d9..55e4896e75 100644
--- a/mod/item.php
+++ b/mod/item.php
@@ -878,7 +878,7 @@ function item_content(App $a)
 	$o = '';
 
 	if (($a->argc >= 3) && ($a->argv[1] === 'drop') && intval($a->argv[2])) {
-		if ($a->isAjax()) {
+		if (DI::mode()->isAjax()) {
 			$o = Item::deleteForUser(['id' => $a->argv[2]], local_user());
 		} else {
 			if (!empty($a->argv[3])) {
@@ -889,7 +889,7 @@ function item_content(App $a)
 			}
 		}
 
-		if ($a->isAjax()) {
+		if (DI::mode()->isAjax()) {
 			// ajax return: [<item id>, 0 (no perm) | <owner id>]
 			echo json_encode([intval($a->argv[2]), intval($o)]);
 			exit();
diff --git a/src/App.php b/src/App.php
index 65ab3be53d..05d592367d 100644
--- a/src/App.php
+++ b/src/App.php
@@ -543,15 +543,6 @@ class App
 		return Core\Theme::getStylesheetPath($this->getCurrentTheme());
 	}
 
-	/**
-	 * @deprecated 2019.09 - use App\Mode->isAjax() instead
-	 * @see        App\Mode::isAjax()
-	 */
-	public function isAjax()
-	{
-		return $this->mode->isAjax();
-	}
-
 	/**
 	 * @deprecated use Arguments->get() instead
 	 *
diff --git a/src/App/Authentication.php b/src/App/Authentication.php
index f9d14171e9..b8073698f2 100644
--- a/src/App/Authentication.php
+++ b/src/App/Authentication.php
@@ -31,6 +31,8 @@ class Authentication
 {
 	/** @var Configuration */
 	private $config;
+	/** @var App\Mode */
+	private $mode;
 	/** @var App\BaseURL */
 	private $baseUrl;
 	/** @var L10n */
@@ -48,6 +50,7 @@ class Authentication
 	 * Authentication constructor.
 	 *
 	 * @param Configuration   $config
+	 * @param App\Mode        $mode
 	 * @param App\BaseURL     $baseUrl
 	 * @param L10n            $l10n
 	 * @param Database        $dba
@@ -55,9 +58,10 @@ class Authentication
 	 * @param User\Cookie     $cookie
 	 * @param Session\ISession $session
 	 */
-	public function __construct(Configuration $config, App\BaseURL $baseUrl, L10n $l10n, Database $dba, LoggerInterface $logger, User\Cookie $cookie, Session\ISession $session)
+	public function __construct(Configuration $config, App\Mode $mode, App\BaseURL $baseUrl, L10n $l10n, Database $dba, LoggerInterface $logger, User\Cookie $cookie, Session\ISession $session)
 	{
 		$this->config  = $config;
+		$this->mode = $mode;
 		$this->baseUrl = $baseUrl;
 		$this->l10n    = $l10n;
 		$this->dba     = $dba;
@@ -404,7 +408,7 @@ class Authentication
 		}
 
 		// Case 2: No valid 2FA session: redirect to code verification page
-		if ($a->isAjax()) {
+		if ($this->mode->isAjax()) {
 			throw new HTTPException\ForbiddenException();
 		} else {
 			$this->baseUrl->redirect('2fa');
diff --git a/src/Module/Admin/Themes/Details.php b/src/Module/Admin/Themes/Details.php
index c45204e98a..f6a3c61b73 100644
--- a/src/Module/Admin/Themes/Details.php
+++ b/src/Module/Admin/Themes/Details.php
@@ -32,7 +32,7 @@ class Details extends BaseAdminModule
 
 			info(L10n::t('Theme settings updated.'));
 
-			if ($a->isAjax()) {
+			if (DI::mode()->isAjax()) {
 				return;
 			}
 
diff --git a/src/Module/Admin/Themes/Embed.php b/src/Module/Admin/Themes/Embed.php
index 0ef72773d2..fc0d3301bf 100644
--- a/src/Module/Admin/Themes/Embed.php
+++ b/src/Module/Admin/Themes/Embed.php
@@ -46,7 +46,7 @@ class Embed extends BaseAdminModule
 
 			info(L10n::t('Theme settings updated.'));
 
-			if ($a->isAjax()) {
+			if (DI::mode()->isAjax()) {
 				return;
 			}
 
diff --git a/src/Module/Debug/ItemBody.php b/src/Module/Debug/ItemBody.php
index 8212ce38b5..d32e1f6c2d 100644
--- a/src/Module/Debug/ItemBody.php
+++ b/src/Module/Debug/ItemBody.php
@@ -31,7 +31,7 @@ class ItemBody extends BaseModule
 		$item = Item::selectFirst(['body'], ['uid' => local_user(), 'id' => $itemId]);
 
 		if (!empty($item)) {
-			if ($app->isAjax()) {
+			if (DI::mode()->isAjax()) {
 				echo str_replace("\n", '<br />', $item['body']);
 				exit();
 			} else {
diff --git a/src/Module/Group.php b/src/Module/Group.php
index b3fe1ba53b..8de4c5033b 100644
--- a/src/Module/Group.php
+++ b/src/Module/Group.php
@@ -24,7 +24,7 @@ class Group extends BaseModule
 	{
 		$a = DI::app();
 
-		if ($a->isAjax()) {
+		if (DI::mode()->isAjax()) {
 			self::ajaxPost();
 		}