diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 7bd365ecb7..a1a76c1e60 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -4,6 +4,7 @@ Yii Framework 2 Change Log
 2.0.16 under development
 ------------------------
 
+- Bug #16991: Removed usage of `utf8_encode()` from `Request::resolvePathInfo()` (GHopperMSK)
 - Bug #16974: Regular Expression Validator to include support for 'u' (UTF-8) modifier (Dzhuneyt)
 - Chg #16941: Set `yii\console\controllers\MigrateController::useTablePrefix` to true as default value (GHopperMSK)
 - Bug #16966: Fix ArrayExpression support in related tables (GHopperMSK)
diff --git a/framework/web/Request.php b/framework/web/Request.php
index c05937579a..f6c1a0de18 100644
--- a/framework/web/Request.php
+++ b/framework/web/Request.php
@@ -922,7 +922,7 @@ class Request extends \yii\base\Request
             | \xF4[\x80-\x8F][\x80-\xBF]{2}      # plane 16
             )*$%xs', $pathInfo)
         ) {
-            $pathInfo = utf8_encode($pathInfo);
+            $pathInfo = $this->utf8Encode($pathInfo);
         }
 
         $scriptUrl = $this->getScriptUrl();
@@ -944,6 +944,26 @@ class Request extends \yii\base\Request
         return (string) $pathInfo;
     }
 
+    /**
+     * Encodes an ISO-8859-1 string to UTF-8
+     * @param string $s
+     * @return string the UTF-8 translation of `s`.
+     * @see https://github.com/symfony/polyfill-php72/blob/master/Php72.php#L24
+     */
+    private function utf8Encode($s)
+    {
+        $s .= $s;
+        $len = \strlen($s);
+        for ($i = $len >> 1, $j = 0; $i < $len; ++$i, ++$j) {
+            switch (true) {
+                case $s[$i] < "\x80": $s[$j] = $s[$i]; break;
+                case $s[$i] < "\xC0": $s[$j] = "\xC2"; $s[++$j] = $s[$i]; break;
+                default: $s[$j] = "\xC3"; $s[++$j] = \chr(\ord($s[$i]) - 64); break;
+            }
+        }
+        return substr($s, 0, $j);
+    }
+
     /**
      * Returns the currently requested absolute URL.
      * This is a shortcut to the concatenation of [[hostInfo]] and [[url]].