diff --git a/apps/files_versions/lib/Versions/IVersionBackend.php b/apps/files_versions/lib/Versions/IVersionBackend.php
index 2cd8cb30cb5f5..d526df6996776 100644
--- a/apps/files_versions/lib/Versions/IVersionBackend.php
+++ b/apps/files_versions/lib/Versions/IVersionBackend.php
@@ -91,7 +91,9 @@ public function read(IVersion $version);
 	 * @param IUser $user
 	 * @param FileInfo $sourceFile
 	 * @param int|string $revision
-	 * @return ISimpleFile
+	 *
+	 * @return File
+	 *
 	 * @since 15.0.0
 	 */
 	public function getVersionFile(IUser $user, FileInfo $sourceFile, $revision): File;
diff --git a/core/Migrations/Version16000Date20190212081545.php b/core/Migrations/Version16000Date20190212081545.php
index e33b475896fe3..feb271b1f01e7 100644
--- a/core/Migrations/Version16000Date20190212081545.php
+++ b/core/Migrations/Version16000Date20190212081545.php
@@ -38,7 +38,8 @@ class Version16000Date20190212081545 extends SimpleMigrationStep {
 	 * @param IOutput $output
 	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
 	 * @param array $options
-	 * @return null|ISchemaWrapper
+	 *
+	 * @return ISchemaWrapper
 	 */
 	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ISchemaWrapper {
 		/** @var ISchemaWrapper $schema */
diff --git a/lib/private/AllConfig.php b/lib/private/AllConfig.php
index 9ccb443aabb83..2eca9d55b2859 100644
--- a/lib/private/AllConfig.php
+++ b/lib/private/AllConfig.php
@@ -129,7 +129,9 @@ public function getSystemValue($key, $default = '') {
 	 *
 	 * @param string $key the key of the value, under which it was saved
 	 * @param mixed $default the default value to be returned if the value isn't set
-	 * @return mixed the value or $default
+	 *
+	 * @return bool
+	 *
 	 * @since 16.0.0
 	 */
 	public function getSystemValueBool(string $key, bool $default = false): bool {
@@ -141,7 +143,9 @@ public function getSystemValueBool(string $key, bool $default = false): bool {
 	 *
 	 * @param string $key the key of the value, under which it was saved
 	 * @param mixed $default the default value to be returned if the value isn't set
-	 * @return mixed the value or $default
+	 *
+	 * @return int
+	 *
 	 * @since 16.0.0
 	 */
 	public function getSystemValueInt(string $key, int $default = 0): int {
@@ -153,7 +157,9 @@ public function getSystemValueInt(string $key, int $default = 0): int {
 	 *
 	 * @param string $key the key of the value, under which it was saved
 	 * @param mixed $default the default value to be returned if the value isn't set
-	 * @return mixed the value or $default
+	 *
+	 * @return string
+	 *
 	 * @since 16.0.0
 	 */
 	public function getSystemValueString(string $key, string $default = ''): string {
diff --git a/lib/private/Authentication/TwoFactorAuth/EnforcementState.php b/lib/private/Authentication/TwoFactorAuth/EnforcementState.php
index 46bcc596d925c..abd0ec7f2e734 100644
--- a/lib/private/Authentication/TwoFactorAuth/EnforcementState.php
+++ b/lib/private/Authentication/TwoFactorAuth/EnforcementState.php
@@ -55,7 +55,7 @@ public function __construct(bool $enforced,
 	}
 
 	/**
-	 * @return string[]
+	 * @return bool
 	 */
 	public function isEnforced(): bool {
 		return $this->enforced;
diff --git a/lib/private/Group/Database.php b/lib/private/Group/Database.php
index 450fffe573e58..27dad809f89be 100644
--- a/lib/private/Group/Database.php
+++ b/lib/private/Group/Database.php
@@ -400,7 +400,8 @@ public function countUsersInGroup(string $gid, string $search = ''): int {
 	 * get the number of disabled users in a group
 	 *
 	 * @param string $search
-	 * @return int|bool
+	 *
+	 * @return int
 	 */
 	public function countDisabledInGroup(string $gid): int {
 		$this->fixDI();
diff --git a/lib/private/User/Session.php b/lib/private/User/Session.php
index 4aa9074b4a4cd..602f779c90120 100644
--- a/lib/private/User/Session.php
+++ b/lib/private/User/Session.php
@@ -317,7 +317,7 @@ public function getLoginName() {
 	}
 
 	/**
-	 * @return mixed
+	 * @return null|string
 	 */
 	public function getImpersonatingUserID(): ?string {