diff --git a/src/Tests/Tests/epv_test_validate_composer.php b/src/Tests/Tests/epv_test_validate_composer.php
index 79ddfd3..a9fbd15 100644
--- a/src/Tests/Tests/epv_test_validate_composer.php
+++ b/src/Tests/Tests/epv_test_validate_composer.php
@@ -47,6 +47,7 @@ public function validateFile(FileInterface $file)
 
 		$this->validateName($file);
 		$this->validateLicense($file);
+		$this->validateVersion($file);
 	}
 
 	/**
@@ -58,17 +59,37 @@ private function validateLicense(ComposerFileInterface $file)
 	{
 		$json = $file->getJson();
 		$this->addMessageIfBooleanTrue(!isset($json['license']), Output::FATAL, 'The license key is missing');
-		$this->addMessageIfBooleanTrue($json['license'] != 'GPL-2.0', Output::ERROR, 'It is required to use the GPL-2.0 as license. MIT is not allowed as per the extension database policies.');
+		$this->addMessageIfBooleanTrue(isset($json['license']) && $json['license'] != 'GPL-2.0', Output::ERROR, 'It is required to use the GPL-2.0 as license. MIT is not allowed as per the extension database policies.');
 	}
 
 	private function validateName(ComposerFileInterface $file)
 	{
 		$json = $file->getJson();
 		$this->addMessageIfBooleanTrue(!isset($json['name']), Output::FATAL, 'The name key is missing');
-		$this->addMessageIfBooleanTrue(strpos($json['name'], '_') !== false, Output::FATAL, 'The namespace should not contain underscores');
+		$this->addMessageIfBooleanTrue(isset($json['name']) && strpos($json['name'], '_') !== false, Output::FATAL, 'The namespace should not contain underscores');
 
 	}
 
+	/**
+	 * @param ComposerFileInterface $file
+	 */
+	private function validateVersion(ComposerFileInterface $file)
+	{
+		$json = $file->getJson();
+
+		if (isset($json['extra']) && isset($json['extra']['soft-require']) && isset($json['extra']['soft-require']['phpbb/phpbb']))
+		{
+			// https://github.com/phpbb/customisation-db/blob/3.1.x/contribution/extension/type.php#L296
+			$regex = '/(<|<=|~|\^|>|>=)([0-9]+(\.[0-9]+)?)\.[*x]/';
+
+			if (preg_match($regex, $json['extra']['soft-require']['phpbb/phpbb']))
+			{
+				$replace = preg_replace($regex, '$1$2', $json['extra']['soft-require']['phpbb/phpbb']);;
+				$this->addMessageIfBooleanTrue(true, Output::ERROR, sprintf('A invalid version constraint is used in soft-require: phpbb/phpbb. You can\'t combine a <|<=|~|\^|>|>= with a *|x. Please replace %s with %s', $json['extra']['soft-require']['phpbb/phpbb'], $replace));
+			}
+		}
+	}
+
 	private function addMessageIfBooleanTrue($addMessage, $type, $message)
 	{
 		if ($addMessage)