diff --git a/src/Core/Cache/CacheDriverFactory.php b/src/Core/Cache/CacheDriverFactory.php
index e9ff4331d7..45cc17a52f 100644
--- a/src/Core/Cache/CacheDriverFactory.php
+++ b/src/Core/Cache/CacheDriverFactory.php
@@ -20,7 +20,7 @@ class CacheDriverFactory
 	 * @return ICacheDriver  The instance of the CacheDriver
 	 * @throws \Exception    The exception if something went wrong during the CacheDriver creation
 	 */
-	public static function create(string $driver) {
+	public static function create($driver) {
 
 		switch ($driver) {
 			case 'memcache':
diff --git a/src/Core/Lock/AbstractLockDriver.php b/src/Core/Lock/AbstractLockDriver.php
index 4c2bfaec95..bcce26129c 100644
--- a/src/Core/Lock/AbstractLockDriver.php
+++ b/src/Core/Lock/AbstractLockDriver.php
@@ -22,7 +22,7 @@ abstract class AbstractLockDriver implements ILockDriver
 	 * @param string key The Name of the lock
 	 * @return bool      Returns true if the lock is set
 	 */
-	protected function hasAcquiredLock(string $key) {
+	protected function hasAcquiredLock($key) {
 		return isset($this->acquireLock[$key]);
 	}
 
@@ -31,7 +31,7 @@ abstract class AbstractLockDriver implements ILockDriver
 	 *
 	 * @param string $key The Name of the lock
 	 */
-	protected function markAcquire(string $key) {
+	protected function markAcquire($key) {
 		$this->acquiredLocks[$key] = true;
 	}
 
@@ -40,7 +40,7 @@ abstract class AbstractLockDriver implements ILockDriver
 	 *
 	 * @param string $key The Name of the lock
 	 */
-	protected function markRelease(string $key) {
+	protected function markRelease($key) {
 		unset($this->acquiredLocks[$key]);
 	}
 
diff --git a/src/Core/Lock/CacheLockDriver.php b/src/Core/Lock/CacheLockDriver.php
index 0adca140d1..1bb768bd0f 100644
--- a/src/Core/Lock/CacheLockDriver.php
+++ b/src/Core/Lock/CacheLockDriver.php
@@ -30,7 +30,7 @@ class CacheLockDriver extends AbstractLockDriver
 	 *
 	 * @return boolean Was the lock successful?
 	 */
-	public function acquireLock(string $key, int $timeout = 120)
+	public function acquireLock($key, $timeout = 120)
 	{
 		$got_lock = false;
 		$start = time();
@@ -71,7 +71,7 @@ class CacheLockDriver extends AbstractLockDriver
 	 *
 	 * @return mixed
 	 */
-	public function releaseLock(string $key)
+	public function releaseLock($key)
 	{
 		$cachekey = get_app()->get_hostname() . ";lock:" . $key;
 		$lock = $this->cache->get($cachekey);
diff --git a/src/Core/Lock/DatabaseLockDriver.php b/src/Core/Lock/DatabaseLockDriver.php
index f9878340cf..9b415753fc 100644
--- a/src/Core/Lock/DatabaseLockDriver.php
+++ b/src/Core/Lock/DatabaseLockDriver.php
@@ -18,7 +18,7 @@ class DatabaseLockDriver extends AbstractLockDriver
 	 *
 	 * @return boolean Was the lock successful?
 	 */
-	public function acquireLock(string $key, int $timeout = 120)
+	public function acquireLock($key, $timeout = 120)
 	{
 		$got_lock = false;
 		$start = time();
@@ -66,7 +66,7 @@ class DatabaseLockDriver extends AbstractLockDriver
 	 *
 	 * @return mixed
 	 */
-	public function releaseLock(string $key)
+	public function releaseLock($key)
 	{
 		dba::delete('locks', ['locked' => false, 'pid' => 0], ['name' => $key, 'pid' => getmypid()]);
 
diff --git a/src/Core/Lock/ILockDriver.php b/src/Core/Lock/ILockDriver.php
index 39e4ba8e89..8744d757f1 100644
--- a/src/Core/Lock/ILockDriver.php
+++ b/src/Core/Lock/ILockDriver.php
@@ -18,7 +18,7 @@ interface ILockDriver
 	 *
 	 * @return boolean Was the lock successful?
 	 */
-	public function acquireLock(string $key, int $timeout = 120);
+	public function acquireLock($key, $timeout = 120);
 
 	/**
 	 * @brief Releases a lock if it was set by us
@@ -27,7 +27,7 @@ interface ILockDriver
 	 *
 	 * @return void
 	 */
-	public function releaseLock(string $key);
+	public function releaseLock($key);
 
 	/**
 	 * @brief Releases all lock that were set by us
diff --git a/src/Core/Lock/SemaphoreLockDriver.php b/src/Core/Lock/SemaphoreLockDriver.php
index 4eb30b9d02..39e3e1d32c 100644
--- a/src/Core/Lock/SemaphoreLockDriver.php
+++ b/src/Core/Lock/SemaphoreLockDriver.php
@@ -18,7 +18,7 @@ class SemaphoreLockDriver extends AbstractLockDriver
 	 *
 	 * @return integer the semaphore key
 	 */
-	private static function semaphoreKey(string $key)
+	private static function semaphoreKey($key)
 	{
 		$temp = get_temppath();
 
@@ -40,7 +40,7 @@ class SemaphoreLockDriver extends AbstractLockDriver
 	 *
 	 * @return boolean Was the lock successful?
 	 */
-	public function acquireLock(string $key, int $timeout = 120)
+	public function acquireLock($key, $timeout = 120)
 	{
 		$this->acquiredLocks[$key] = sem_get(self::semaphoreKey($key));
 		if ($this->acquiredLocks[$key]) {
@@ -55,7 +55,7 @@ class SemaphoreLockDriver extends AbstractLockDriver
 	 *
 	 * @return mixed
 	 */
-	public function releaseLock(string $key)
+	public function releaseLock($key)
 	{
 		if (empty($this->acquiredLocks[$key])) {
 			return false;