diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f6bf015a..6cbb1d6f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,6 +12,8 @@ jobs:
                 uses: shivammathur/setup-php@v2
                 with:
                     php-version: ${{ matrix.php-version }}
+                env:
+                    update: true
             -   name: Composer Install
                 run: composer install --classmap-authoritative --no-interaction --no-cache
             -   name: Lint
@@ -31,6 +33,8 @@ jobs:
                 uses: shivammathur/setup-php@v2
                 with:
                     php-version: '8.1'
+                env:
+                    update: true
             -   name: Composer Install
                 run: composer install --classmap-authoritative --no-interaction --no-cache
             -   name: PHP_CodeSniffer
@@ -52,6 +56,8 @@ jobs:
                 uses: shivammathur/setup-php@v2
                 with:
                     php-version: ${{ matrix.php-version }}
+                env:
+                    update: true
             -   name: Composer Install
                 run: composer install --classmap-authoritative --no-interaction --no-cache --ignore-platform-req=php
             -   name: Setup Secure Shell Functional Tests
diff --git a/build/psalm_baseline.xml b/build/psalm_baseline.xml
index 354cb36f..bd340c6b 100644
--- a/build/psalm_baseline.xml
+++ b/build/psalm_baseline.xml
@@ -15354,14 +15354,6 @@
       <code>$type</code>
     </UnusedVariable>
   </file>
-  <file src="../phpseclib/bootstrap.php">
-    <InvalidOperand occurrences="1">
-      <code>ini_get('mbstring.func_overload')</code>
-    </InvalidOperand>
-    <PossiblyFalseOperand occurrences="1">
-      <code>ini_get('mbstring.func_overload')</code>
-    </PossiblyFalseOperand>
-  </file>
   <file src="../tests/Functional/Net/SFTPLargeFileTest.php">
     <PropertyNotSetInConstructor occurrences="3">
       <code>SFTPLargeFileTest</code>
diff --git a/composer.json b/composer.json
index c47d48c1..38fb2826 100644
--- a/composer.json
+++ b/composer.json
@@ -75,9 +75,6 @@
         "ext-dom": "Install the DOM extension to load XML formatted public keys."
     },
     "autoload": {
-        "files": [
-            "phpseclib/bootstrap.php"
-        ],
         "psr-4": {
             "phpseclib3\\": "phpseclib/"
         }
diff --git a/phpseclib/bootstrap.php b/phpseclib/bootstrap.php
deleted file mode 100644
index 7aededc9..00000000
--- a/phpseclib/bootstrap.php
+++ /dev/null
@@ -1,24 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-/**
- * Bootstrapping File for phpseclib
- *
- * composer isn't a requirement for phpseclib 2.0 but this file isn't really required
- * either. it's a bonus for those using composer but if you're not phpseclib will
- * still work
- *
- * @license http://www.opensource.org/licenses/mit-license.html MIT License
- */
-
-if (extension_loaded('mbstring')) {
-    // 2 - MB_OVERLOAD_STRING
-    // mbstring.func_overload is deprecated in php 7.2 and removed in php 8.0.
-    if (version_compare(PHP_VERSION, '8.0.0') < 0 && ini_get('mbstring.func_overload') & 2) {
-        throw new UnexpectedValueException(
-            'Overloading of string functions using mbstring.func_overload ' .
-            'is not supported by phpseclib.'
-        );
-    }
-}