diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a819f5b..c99a22e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php: [ 7.4, 8.0 ]
+        php: [ 7.4, 8.0, 8.1 ]
         redis-version: [4, 5, 6]
     steps:
       - uses: actions/checkout@v2
diff --git a/README.md b/README.md
index e4c603f..12f5127 100755
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ Kdyby/Redis
 Requirements
 ------------
 
-Kdyby/Redis requires PHP 7.1 or newer.
+Kdyby/Redis requires PHP 7.4 or newer.
 
 - [Nette Framework](https://github.com/nette/nette)
 - [Redis database](http://redis.io)
diff --git a/src/Kdyby/Redis/RedisClient.php b/src/Kdyby/Redis/RedisClient.php
index 8530a84..8af46b7 100644
--- a/src/Kdyby/Redis/RedisClient.php
+++ b/src/Kdyby/Redis/RedisClient.php
@@ -720,6 +720,7 @@ public function offsetExists($offset): bool
 	 * @param string|int $offset
 	 * @return mixed
 	 */
+	#[\ReturnTypeWillChange]
 	public function offsetGet($offset)
 	{
 		return $this->__get($offset);
diff --git a/src/Kdyby/Redis/RedisSessionHandler.php b/src/Kdyby/Redis/RedisSessionHandler.php
index c2ec9f2..5a7310b 100644
--- a/src/Kdyby/Redis/RedisSessionHandler.php
+++ b/src/Kdyby/Redis/RedisSessionHandler.php
@@ -102,7 +102,7 @@ public function open($savePath, $sessionName): bool
 	 * @throws \Kdyby\Redis\Exception\SessionHandlerException
 	 * @return string
 	 */
-	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
+	#[\ReturnTypeWillChange]
 	public function read($id): string
 	{
 		return (string) $this->client->get($this->lock($id));
@@ -138,7 +138,6 @@ public function destroy($id): bool
 		return TRUE;
 	}
 
-	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
 	public function close(): bool
 	{
 		foreach ($this->ssIds as $key) {
@@ -150,9 +149,9 @@ public function close(): bool
 	}
 
 	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
-	public function gc($maxLifeTime): bool
+	public function gc($maxLifeTime): int
 	{
-		return TRUE;
+		return 1;
 	}
 
 	protected function lock(string $id): string
diff --git a/tests/KdybyTests/Redis/SessionHandlerDecorator.php b/tests/KdybyTests/Redis/SessionHandlerDecorator.php
index 59c74eb..d821727 100644
--- a/tests/KdybyTests/Redis/SessionHandlerDecorator.php
+++ b/tests/KdybyTests/Redis/SessionHandlerDecorator.php
@@ -54,13 +54,9 @@ private function log(string $msg): void
 	/**
 	 * @param string $savePath
 	 * @param string $sessionId
-	 * @return bool
 	 */
 	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
-	public function open(
-		$savePath,
-		$sessionId
-	)
+	public function open($savePath, $sessionId): bool
 	{
 		$this->log(\sprintf('%s: %s', __FUNCTION__, $sessionId));
 		$this->openedSessionCalls[] = \array_merge([__FUNCTION__], \func_get_args());
@@ -68,11 +64,7 @@ public function open(
 		return $this->handler->open($savePath, $sessionId);
 	}
 
-	/**
-	 * @return bool
-	 */
-	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
-	public function close()
+	public function close(): bool
 	{
 		$this->log(__FUNCTION__);
 		$this->openedSessionCalls[] = \array_merge([__FUNCTION__], \func_get_args());
@@ -84,10 +76,11 @@ public function close()
 
 	/**
 	 * @param string $sessionId
-	 * @return string
+	 * @return string|false
 	 * @throws \Throwable
 	 */
 	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
+	#[\ReturnTypeWillChange]
 	public function read($sessionId)
 	{
 		$this->log(\sprintf('%s: %s', __FUNCTION__, $sessionId));
@@ -102,11 +95,10 @@ public function read($sessionId)
 
 	/**
 	 * @param string $sessionId
-	 * @return bool
 	 * @throws \Throwable
 	 */
 	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
-	public function destroy($sessionId)
+	public function destroy($sessionId): bool
 	{
 		$this->log(\sprintf('%s: %s', __FUNCTION__, $sessionId));
 		$this->openedSessionCalls[] = \array_merge([__FUNCTION__], \func_get_args());
@@ -121,14 +113,10 @@ public function destroy($sessionId)
 	/**
 	 * @param string $sessionId
 	 * @param string $sessionData
-	 * @return bool
 	 * @throws \Throwable
 	 */
 	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
-	public function write(
-		$sessionId,
-		$sessionData
-	)
+	public function write($sessionId, $sessionData): bool
 	{
 		$this->log(\sprintf('%s: %s', __FUNCTION__, $sessionId));
 		$this->openedSessionCalls[] = \array_merge([__FUNCTION__], \func_get_args());
@@ -142,9 +130,10 @@ public function write(
 
 	/**
 	 * @param int $maxlifetime
-	 * @return bool
+	 * @return int|false
 	 */
 	// phpcs:disable SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint,SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
+	#[\ReturnTypeWillChange]
 	public function gc($maxlifetime)
 	{
 		$this->log(__FUNCTION__);