diff --git a/changelog/unreleased/40945 b/changelog/unreleased/40945
new file mode 100644
index 000000000000..e9ba4244ed31
--- /dev/null
+++ b/changelog/unreleased/40945
@@ -0,0 +1,6 @@
+Bugfix: fix usort callback functions to return integers
+
+Calls to the PHP usort function have been refactored so that the callback
+function used always correctly returns an integer.
+
+https://github.com/owncloud/core/pull/40945
diff --git a/core/Command/App/CheckCode.php b/core/Command/App/CheckCode.php
index 50eb4f6feffc..c6b7f6c75410 100644
--- a/core/Command/App/CheckCode.php
+++ b/core/Command/App/CheckCode.php
@@ -110,7 +110,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 				$output->writeln(" {$count} errors");
 			}
 			\usort($errors, function ($a, $b) {
-				return $a['line'] >$b['line'];
+				return $a['line'] - $b['line'];
 			});
 
 			foreach ($errors as $p) {
diff --git a/lib/private/DB/MigrationService.php b/lib/private/DB/MigrationService.php
index 340f6383de04..d579173c75dd 100644
--- a/lib/private/DB/MigrationService.php
+++ b/lib/private/DB/MigrationService.php
@@ -195,7 +195,7 @@ protected function findMigrations() {
 
 		$files = \array_keys(\iterator_to_array($iterator));
 		\uasort($files, function ($a, $b) {
-			return (\basename($a) < \basename($b)) ? -1 : 1;
+			return \strcmp(\basename($a), \basename($b));
 		});
 
 		$migrations = [];
diff --git a/lib/private/Preview/TXT.php b/lib/private/Preview/TXT.php
index 5caa3ac4551b..1764c4dbe3dd 100644
--- a/lib/private/Preview/TXT.php
+++ b/lib/private/Preview/TXT.php
@@ -146,7 +146,7 @@ private function getFontFile(array $info): string {
 			if ($a === $b) {
 				return 0;
 			}
-			return ($a < $b) ? 1 : -1;
+			return ($b - $a);
 		});
 		// Information is ordered by counted chars, from highest number of counted chars to lowest.
 		foreach ($countInfo as $key => $value) {
diff --git a/lib/private/Settings/SettingsManager.php b/lib/private/Settings/SettingsManager.php
index f1c79447e23d..cdaaacd173b6 100644
--- a/lib/private/Settings/SettingsManager.php
+++ b/lib/private/Settings/SettingsManager.php
@@ -475,14 +475,15 @@ protected function loadSection($type, $sectionID) {
 
 	/**
 	 * Sort the array of ISettings or ISections by their priority attribute
-	 * @param array $objects (ISections of ISettings)
+	 * A lower priority number means that the item should appear first.
+	 * @param array $objects (ISections or ISettings)
 	 * @return array
 	 */
 	protected function sortOrder($objects) {
 		\usort($objects, function ($a, $b) {
 			/** @var ISection | ISettings $a */
 			/** @var ISection | ISettings $b */
-			return $a->getPriority() < $b->getPriority();
+			return $b->getPriority() - $a->getPriority();
 		});
 		return $objects;
 	}
diff --git a/tests/lib/Files/Cache/CacheTest.php b/tests/lib/Files/Cache/CacheTest.php
index 0eb7992c126c..84c770dbe4c9 100644
--- a/tests/lib/Files/Cache/CacheTest.php
+++ b/tests/lib/Files/Cache/CacheTest.php
@@ -366,7 +366,7 @@ public function testSearchByTag() {
 		$this->assertCount(2, $results);
 
 		\usort($results, function ($value1, $value2) {
-			return $value1['name'] >= $value2['name'];
+			return \strcmp($value1['name'], $value2['name']);
 		});
 
 		$this->assertEquals('folder', $results[0]['name']);
@@ -382,7 +382,7 @@ public function testSearchByTag() {
 		$this->assertCount(3, $results);
 
 		\usort($results, function ($value1, $value2) {
-			return $value1['name'] >= $value2['name'];
+			return \strcmp($value1['name'], $value2['name']);
 		});
 
 		$this->assertEquals('folder', $results[0]['name']);