diff --git a/src/Core/Installer.php b/src/Core/Installer.php
index b84bcd916e..912406a298 100644
--- a/src/Core/Installer.php
+++ b/src/Core/Installer.php
@@ -405,6 +405,13 @@ class Installer
 		);
 		$returnVal = $returnVal ? $status : false;
 
+		$status = $this->checkFunction('json_encode',
+			L10n::t('JSON PHP module'),
+			L10n::t('Error: JSON PHP module required but not installed.'),
+			true
+		);
+		$returnVal = $returnVal ? $status : false;
+
 		$status = $this->checkFunction('imagecreatefromjpeg',
 			L10n::t('GD graphics PHP module'),
 			L10n::t('Error: GD graphics PHP module with JPEG support required but not installed.'),