diff --git a/lam/lib/baseModule.inc b/lam/lib/baseModule.inc
index 27d9f0357..7adff2f90 100644
--- a/lam/lib/baseModule.inc
+++ b/lam/lib/baseModule.inc
@@ -554,10 +554,10 @@ abstract class baseModule {
 	 * (e.g. posixAccount_homeDirectory) to avoid naming conflicts.
 	 *
 	 * @param string $typeId type id (user, group, host, ...)
-	 * @return htmlElement meta HTML object
+	 * @return htmlResponsiveRow|null meta HTML object
 	 *
 	 * @see baseModule::get_metaData()
-	 * @see htmlElement
+	 * @see htmlResponsiveRow
 	 */
 	public function get_profileOptions($typeId) {
 		return $this->meta['profile_options'] ?? null;
diff --git a/lam/lib/modules.inc b/lam/lib/modules.inc
index ba7d17536..c9a518ad7 100644
--- a/lam/lib/modules.inc
+++ b/lam/lib/modules.inc
@@ -853,16 +853,12 @@ class accountContainer {
 	/**
 	 * Returns the account module with the given class name
 	 *
-	 * @param string $name class name (e.g. posixAccount)
-	 * @return baseModule account module
+	 * @template T of baseModule
+	 * @param class-string<T> $name class name (e.g. posixAccount)
+	 * @return T|null account module
 	 */
-	public function getAccountModule($name) {
-		if (isset($this->module[$name])) {
-			return $this->module[$name];
-		}
-		else {
-			return null;
-		}
+	public function getAccountModule(string $name): ?baseModule {
+		return $this->module[$name] ?? null;
 	}
 
 	/**
diff --git a/lam/lib/modules/windowsUser.inc b/lam/lib/modules/windowsUser.inc
index 8c7cf2818..ea484c799 100644
--- a/lam/lib/modules/windowsUser.inc
+++ b/lam/lib/modules/windowsUser.inc
@@ -3751,21 +3751,7 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 	}
 
 	/**
-	 * Checks if all input values are correct and returns the LDAP attributes which should be changed.
-	 * <br>Return values:
-	 * <br>messages: array of parameters to create status messages
-	 * <br>add: array of attributes to add
-	 * <br>del: array of attributes to remove
-	 * <br>mod: array of attributes to modify
-	 * <br>info: array of values with informational value (e.g. to be used later by pre/postModify actions)
-	 *
-	 * Calling this method does not require the existence of an enclosing {@link accountContainer}.
-	 *
-	 * @param string $fields input fields
-	 * @param array $attributes LDAP attributes
-	 * @param boolean $passwordChangeOnly indicates that the user is only allowed to change his password and no LDAP content is readable
-	 * @param array $readOnlyFields list of read-only fields
-	 * @return array messages and attributes (array('messages' => [], 'add' => array('mail' => array('test@test.com')), 'del' => [], 'mod' => [], 'info' => []))
+	 * {@inheritDoc}
 	 */
 	function checkSelfServiceOptions($fields, $attributes, $passwordChangeOnly, $readOnlyFields) {
 		$return = ['messages' => [], 'add' => [], 'del' => [], 'mod' => [], 'info' => []];
@@ -3936,14 +3922,14 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 	 * Returns if the account is currently deactivated.
 	 *
 	 * @param array $attrs LDAP attributes
-	 * @return boolean is deactivated
+	 * @return bool is deactivated
 	 */
-	public static function isDeactivated($attrs) {
+	public static function isDeactivated($attrs): bool {
 		$myAttrs = array_change_key_case($attrs);
 		if (!isset($myAttrs['useraccountcontrol'][0])) {
 			return false;
 		}
-		return intval($myAttrs['useraccountcontrol'][0]) & self::AC_ACCOUNT_DISABLED;
+		return (intval($myAttrs['useraccountcontrol'][0]) & self::AC_ACCOUNT_DISABLED) === self::AC_ACCOUNT_DISABLED;
 	}
 
 	/**
@@ -4007,9 +3993,9 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 	/**
 	 * Unlocks the user password. This resets 'lockoutTime' to 0.
 	 *
-	 * @param array|null $attributes LDAP attributes
+	 * @param array<string, array<string>|string>|null $attributes LDAP attributes
 	 */
-	public function unlockPassword(?array &$attributes = null) {
+	public function unlockPassword(?array &$attributes = null): void {
 		if ($attributes === null) {
 			$attributes = &$this->attributes;
 		}
@@ -4022,7 +4008,7 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 	 * Sets if the account is currently deactivated.
 	 *
 	 * @param boolean $deactivated is deactivated
-	 * @param array $attrs LDAP attributes to modify (default $this->attributes)
+	 * @param array<string, array<string>|string>|null $attrs LDAP attributes to modify (default $this->attributes)
 	 */
 	public function setIsDeactivated($deactivated, &$attrs = null) {
 		if ($attrs == null) {
@@ -4044,13 +4030,13 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 	 * Returns if the account requires a smartcard to login.
 	 *
 	 * @param array $attrs LDAP attributes
-	 * @return boolean requires a smartcard
+	 * @return bool requires a smartcard
 	 */
-	public static function isSmartCardRequired($attrs) {
+	public static function isSmartCardRequired($attrs): bool {
 		if (!isset($attrs['useraccountcontrol'][0])) {
 			return false;
 		}
-		return intval($attrs['useraccountcontrol'][0]) & self::AC_SMARTCARD_REQUIRED;
+		return (intval($attrs['useraccountcontrol'][0]) & self::AC_SMARTCARD_REQUIRED) === self::AC_SMARTCARD_REQUIRED;
 	}
 
 	/**
@@ -4076,13 +4062,13 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 	 * Returns if the account never expires.
 	 *
 	 * @param array $attrs LDAP attributes
-	 * @return boolean never expires
+	 * @return bool never expires
 	 */
-	public static function isNeverExpiring($attrs) {
+	public static function isNeverExpiring($attrs): bool {
 		if (!isset($attrs['useraccountcontrol'][0])) {
 			return false;
 		}
-		return intval($attrs['useraccountcontrol'][0]) & self::AC_PWD_NEVER_EXPIRES;
+		return (intval($attrs['useraccountcontrol'][0]) & self::AC_PWD_NEVER_EXPIRES) === self::AC_PWD_NEVER_EXPIRES;
 	}
 
 	/**
@@ -4286,9 +4272,9 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 	 * Returns a value in file time (100 ns since 1601-01-01).
 	 *
 	 * @param integer $value time value as int
-	 * @return DateTime time value
+	 * @return DateTime|null time value
 	 */
-	public static function getFileTime($value) {
+	public static function getFileTime($value): ?DateTime {
 		if (empty($value) || !get_preg($value, 'digit')) {
 			return null;
 		}
@@ -4806,7 +4792,7 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 	 */
 	public function getListRenderFunction(string $attributeName): ?callable {
 		if ($attributeName === 'mail') {
-			return function(array $entry, string $attribute): ?htmlElement {
+			return function(array $entry, string $attribute): htmlElement {
 				$group = new htmlGroup();
 				if (isset($entry[$attribute][0]) && ($entry[$attribute][0] != '')) {
 					for ($i = 0; $i < count($entry[$attribute]); $i++) {
@@ -4848,10 +4834,10 @@ class windowsUser extends baseModule implements passwordService, AccountStatusPr
 			};
 		}
 		elseif ($attributeName === 'accountexpires') {
-			return fn(array $entry, string $attribute): ?htmlElement => new htmlOutputText($this->formatAccountExpires($entry));
+			return fn(array $entry, string $attribute): htmlElement => new htmlOutputText($this->formatAccountExpires($entry));
 		}
 		elseif (($attributeName === 'whencreated') || ($attributeName === 'whenchanged')) {
-			return function(array $entry, string $attribute): ?htmlElement {
+			return function(array $entry, string $attribute): htmlElement {
 				$value = ' - ';
 				if (!empty($entry[$attribute][0])) {
 					$value = formatLDAPTimestamp($entry[$attribute][0]);
diff --git a/lam/lib/status.inc b/lam/lib/status.inc
index 550517dbf..5290e6f39 100644
--- a/lam/lib/status.inc
+++ b/lam/lib/status.inc
@@ -38,12 +38,12 @@
  * <br> It may be formatted with special color/link/bold tags.
  * @param string $MessageText The text of the status message.
  * <br> It may be formatted with special color/link/bold tags. This parameter is optional.
- * @param array|string $MessageVariables The variables that are used to replace the spacers (%s) in the
+ * @param array|string|null $MessageVariables The variables that are used to replace the spacers (%s) in the
  * submitted text. This parameter is optional.
  * @param bool $returnOutput if set to true this function will return the generated HTML code instead of printing it directly (default: false)
  * @return string HTML code if $returnOutput is set to true, otherwise null
  */
-function StatusMessage($MessageTyp, $MessageHeadline, $MessageText = '', array|string $MessageVariables = [], bool $returnOutput = false): string {
+function StatusMessage($MessageTyp, $MessageHeadline, $MessageText = '', array|string|null $MessageVariables = [], bool $returnOutput = false): string {
 	/* Setting CSS-StyleSheet class depending on the $MessageTyp and rewriting $MessageTyp with a readable string. */
 	if ($MessageTyp == "INFO") {
 		$class = "class=\"statusInfo lam-status-message\"";
@@ -75,9 +75,12 @@ function StatusMessage($MessageTyp, $MessageHeadline, $MessageText = '', array|s
 			$output = $format;
 		}
 	}
-	else {
+	elseif ($MessageVariables !== null) {
 		$output = sprintf($format, $MessageVariables);
 	}
+	else {
+		$output = $format;
+	}
 	if ($returnOutput) {
 		return $output;
 	}