diff --git a/.github/docker-compose.yml b/.github/docker-compose.yml
index e630f21..55835c5 100644
--- a/.github/docker-compose.yml
+++ b/.github/docker-compose.yml
@@ -75,7 +75,6 @@ services:
       dockerfile: ./swoole.dockerfile
       args:
         SWOOLE_VERSION: ${SWOOLE_VERSION}
-        PHP_VERSION: ${PHP_VERSION}
     depends_on:
       - zookeeper
       - kafka1
diff --git a/.github/swoole.dockerfile b/.github/swoole.dockerfile
index 00613e5..a83aa6f 100644
--- a/.github/swoole.dockerfile
+++ b/.github/swoole.dockerfile
@@ -1,6 +1,5 @@
 ARG SWOOLE_VERSION
-ARG PHP_VERSION
-FROM phpswoole/swoole:${SWOOLE_VERSION}-php${PHP_VERSION}
+FROM phpswoole/swoole:${SWOOLE_VERSION}
 
 # apt
 RUN apt update
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c92054e..66f3efc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,13 +9,19 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [7.1, 7.2, 7.3, 7.4, "8.0"]
+        swoole: [
+          4.5-php7.1,
+          4.5-php7.2,
+          4.5-php7.3,
+          4.5-php7.4,
+          4.5-php8.0,
+          php8.1,
+        ]
         kafka: [1.0.0, 2.11-1.1.1, 2.13-2.6.0, 2.13-2.7.0]
 
     env:
-      PHP_VERSION: ${{ matrix.php }}
+      SWOOLE_VERSION: ${{ matrix.swoole }}
       KAFKA_VERSION: ${{ matrix.kafka }}
-      SWOOLE_VERSION: "4.5"
       KAFKA_HOST: kafka1
       KAFKA_PLAINTEXT_PORT: 9092
       KAFKA_SASL_PLAINTEXT_PORT: 9093
diff --git a/.github/workflows/phpcs.yml b/.github/workflows/phpcs.yml
index f6279ad..f2b2186 100644
--- a/.github/workflows/phpcs.yml
+++ b/.github/workflows/phpcs.yml
@@ -9,13 +9,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [7.4]
+        swoole: [4.5-php7.1]
         kafka: [2.13-2.7.0]
 
     env:
-      PHP_VERSION: ${{ matrix.php }}
+      SWOOLE_VERSION: ${{ matrix.swoole }}
       KAFKA_VERSION: ${{ matrix.kafka }}
-      SWOOLE_VERSION: 4.5
 
     steps:
       - uses: actions/checkout@v2
@@ -34,4 +33,4 @@ jobs:
           docker exec swoole composer update
 
       - name: Test
-        run: docker exec swoole ./vendor/bin/php-cs-fixer fix --dry-run
+        run: docker exec swoole ./vendor/bin/php-cs-fixer fix --dry-run --diff
diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
index a03a184..90ad3f9 100644
--- a/.github/workflows/phpstan.yml
+++ b/.github/workflows/phpstan.yml
@@ -9,13 +9,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [7.4]
+        swoole: [4.5-php7.1]
         kafka: [2.13-2.7.0]
 
     env:
-      PHP_VERSION: ${{ matrix.php }}
+      SWOOLE_VERSION: ${{ matrix.swoole }}
       KAFKA_VERSION: ${{ matrix.kafka }}
-      SWOOLE_VERSION: 4.5
 
     steps:
       - uses: actions/checkout@v2
diff --git a/composer.json b/composer.json
index 88f82d2..3e9368a 100644
--- a/composer.json
+++ b/composer.json
@@ -6,7 +6,8 @@
         "php": ">=7.1",
         "google/crc32": "^0.1.0",
         "exussum12/xxhash": "^1.0.0",
-        "chdemko/sorted-collections": "^1.0"
+        "chdemko/sorted-collections": "^1.0",
+        "symfony/polyfill-php81": "^1.23"
     },
     "require-dev": {
         "phpunit/phpunit": "^7.5|^8.0|^9.0",
@@ -30,4 +31,4 @@
         "swoole-test": "export KAFKA_CLIENT_CLASS=\"\\longlang\\phpkafka\\Client\\SwooleClient\" && ./swoole-phpunit",
         "test-coverage": "php -dzend_extension=xdebug ./vendor/bin/phpunit"
     }
-}
\ No newline at end of file
+}
diff --git a/src/Protocol/AbstractStruct.php b/src/Protocol/AbstractStruct.php
index 059f3ec..8421830 100644
--- a/src/Protocol/AbstractStruct.php
+++ b/src/Protocol/AbstractStruct.php
@@ -205,6 +205,7 @@ public function getFlexibleVersions(): array
      *
      * @return array
      */
+    #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return $this->toArray();