diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index dd4ff449450..1935d097811 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -10,7 +10,6 @@ Yii Framework 2 Change Log
 - Bug #20256: Add support for dropping views in MSSQL server when running migrate/fresh (ambrozt)
 - Enh #20248: Add support for attaching behaviors in configurations with Closure (timkelty)
 - Enh #20268: Minor optimisation in `\yii\helpers\BaseArrayHelper::map` (chriscpty)
-- Enh #20268: Add `\yii\helpers\BaseStringHelper::contains()` as a polyfill for `str_contains` (chriscpty)
 
 2.0.51 July 18, 2024
 --------------------
diff --git a/framework/helpers/BaseArrayHelper.php b/framework/helpers/BaseArrayHelper.php
index 334f55112e0..bc770f96cb7 100644
--- a/framework/helpers/BaseArrayHelper.php
+++ b/framework/helpers/BaseArrayHelper.php
@@ -595,7 +595,7 @@ public static function getColumn($array, $name, $keepKeys = true)
      */
     public static function map($array, $from, $to, $group = null)
     {
-        if (is_string($from) && is_string($to) && $group === null && !\yii\helpers\StringHelper::contains($from, '.') && !\yii\helpers\StringHelper::contains($to, '.')) {
+        if (is_string($from) && is_string($to) && $group === null && strpos($from, '.') === false && strpos($to, '.') === false) {
             return array_column($array, $to, $from);
         }
         $result = [];
diff --git a/framework/helpers/BaseStringHelper.php b/framework/helpers/BaseStringHelper.php
index bcecca8485b..5854e29766d 100644
--- a/framework/helpers/BaseStringHelper.php
+++ b/framework/helpers/BaseStringHelper.php
@@ -226,30 +226,6 @@ protected static function truncateHtml($string, $count, $suffix, $encoding = fal
         return $generator->generateFromTokens($truncated) . ($totalCount >= $count ? $suffix : '');
     }
 
-    /**
-     * @param string $string The input string.
-     * @param string $needle Part to search inside $string
-     * @param bool $caseSensitive Case sensitive search. Default is true. When case sensitive is enabled, `$with` must
-     * exactly match the starting of the string in order to get a true value.
-     * @return bool
-     */
-    public static function contains($string, $needle, $caseSensitive = true)
-    {
-        $string = (string)$string;
-        $needle = (string)$needle;
-
-        if ($caseSensitive) {
-            // can be replaced with just the str_contains call when minimum supported PHP version is raised to 8.0 or higher
-            if (function_exists('str_contains')) {
-                return str_contains($string, $needle);
-            }
-            $encoding = Yii::$app ? Yii::$app->charset : 'UTF-8';
-            return mb_strpos($string, $needle, 0, $encoding) !== false;
-        }
-        $encoding = Yii::$app ? Yii::$app->charset : 'UTF-8';
-        return mb_stripos($string, $needle, 0, $encoding) !== false;
-    }
-
     /**
      * Check if given string starts with specified substring. Binary and multibyte safe.
      *
diff --git a/tests/framework/helpers/StringHelperTest.php b/tests/framework/helpers/StringHelperTest.php
index 49ffee0d876..5f222ec4e7a 100644
--- a/tests/framework/helpers/StringHelperTest.php
+++ b/tests/framework/helpers/StringHelperTest.php
@@ -150,15 +150,6 @@ public function testTruncateWords()
         $this->assertEquals('<span><img src="image.png" />This is a test</span><strong> for</strong>...', StringHelper::truncateWords('<span><img src="image.png" />This is a test</span><strong> for a sentance</strong>', 5, '...', true));
     }
 
-    public function testContains()
-    {
-        $this->assertEquals(true, StringHelper::contains('Test', 'st'));
-        $this->assertEquals(false, StringHelper::contains('Test', 'ts'));
-        $this->assertEquals(false, StringHelper::contains('Test', 'St'));
-        $this->assertEquals(true, StringHelper::contains('Test', 'St', false));
-        $this->assertEquals(false, StringHelper::contains('Test', 'Ste', false));
-    }
-
     /**
      * @dataProvider providerStartsWith
      * @param bool $result