diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 7a867533d8..c6f850ad53 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -20,7 +20,7 @@ jobs:
       fail-fast: false
       matrix:
         operating-system: [ ubuntu-18.04 ]
-        php: [ '5.4', '5.5', '5.6', '7.1', '7.2', '7.3', '7.4', '8.0' ]
+        php: [ '5.4', '5.5', '5.6', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1' ]
         db: [ mysql, pgsql ]
         include:
           - db: mysql
@@ -33,6 +33,7 @@ jobs:
             dbuser: 'postgres'
             dbpass: 'password'
             dbname: 'eccube_db'
+
     services:
       mysql:
         image: mysql:5.7
diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
index e94b56e888..ec8e8b909a 100644
--- a/.github/workflows/phpstan.yml
+++ b/.github/workflows/phpstan.yml
@@ -35,7 +35,7 @@ jobs:
     - name: Setup PHP
       uses: nanasess/setup-php@master
       with:
-        php-version: '8.0'
+        php-version: '8.1'
     - name: composer install
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # 暫定対応
diff --git a/data/class/SC_Initial.php b/data/class/SC_Initial.php
index 83c5aa204e..f4de21a1f4 100644
--- a/data/class/SC_Initial.php
+++ b/data/class/SC_Initial.php
@@ -147,7 +147,9 @@ public function phpconfigInit()
             ini_set('mbstring.http_input', CHAR_CODE);
             ini_set('mbstring.http_output', CHAR_CODE);
         }
-        ini_set('auto_detect_line_endings', 1);
+        if (PHP_VERSION_ID < 80100) {
+            ini_set('auto_detect_line_endings', 1);
+        }
         ini_set('default_charset', CHAR_CODE);
         ini_set('mbstring.detect_order', 'auto');
         ini_set('mbstring.substitute_character', 'none');
diff --git a/data/class/helper/SC_Helper_CSV.php b/data/class/helper/SC_Helper_CSV.php
index a7742414b1..7a2d0a7c77 100644
--- a/data/class/helper/SC_Helper_CSV.php
+++ b/data/class/helper/SC_Helper_CSV.php
@@ -386,7 +386,8 @@ public static function &fopen_for_output_csv($filename = 'php://output')
  */
 class php_user_filter_lf2crlf extends php_user_filter
 {
-    function filter($in, $out, &$consumed, $closing)
+    #[\ReturnTypeWillChange]
+    public function filter($in, $out, &$consumed, $closing)
     {
         while ($bucket = stream_bucket_make_writeable($in)) {
             $bucket->data = preg_replace("/[\r\n]+$/", "\r\n", $bucket->data);