diff --git a/CHANGELOG.md b/CHANGELOG.md
index b1e2311..ac82ef4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,27 @@ Pico Composer Installer Changelog
           refer to both the UPGRADE and NEWS sections of the docs for more
           details.
 
+### Version 2.0.2
+Released: -
+
+```
+* [Fixed] Update README.md for v2.0
+```
+
+### Version 2.0.1
+Released: 2025-12-23
+
+```
+* [Fixed] Fix implicit nullable deprecation
+```
+
+### Version 2.0.0
+Released: 2025-12-22
+
+```
+* [Changed] Update to a Composer 2.x plugin (no functional changes)
+```
+
 ### Version 1.0.1
 Released: 2019-11-24
 
diff --git a/README.md b/README.md
index 580a8ae..93fdfe0 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@ Pico Composer Installer
 
 This is the repository of Pico's official [Composer][] installer.
 
-Pico is a stupidly simple, blazing fast, flat file CMS. See http://picocms.org/ for more info.
+Pico is a stupidly simple, blazing fast, flat file CMS. See https://picocms.org/ for more info.
 
 This Composer plugin is responsible for installing Pico plugins and themes using the Composer package manager (i.e. by running `composer install` on the command line). It assumes responsibility for packages that identify as `{ "type": "pico-plugin" }` and `{ "type": "pico-theme" }` in their `composer.json` and instructs Composer to install these packages to Pico's `plugins/` and `themes/` folder respectively.
 
@@ -19,14 +19,14 @@ Install
 If you've used Pico's official composer starter project ([`picocms/pico-composer`][pico-composer]), your website's `composer.json` (the "root package") already depends on `picocms/composer-installer`. If this isn't true, run the following to load it from [Packagist.org][]:
 
 ```shell
-$ composer require picocms/composer-installer:^1.0
+$ composer require picocms/composer-installer:^2.0
 ```
 
 The Composer plugin tries to automatically register itself for the `post-autoload-dump` event. This is a prerequisite for the installer to create a `vendor/pico-plugin.php`. If the installer was successful in doing so, you'll see the following three lines when running `composer install` or `composer update`:
 
 ```
 Generating autoload files
-> Pico\Composer\Installer\PluginInstaller::postAutoloadDump
+> picocms\\ComposerInstaller\\Installer::postAutoloadDump
 Creating Pico plugins file
 ```
 
@@ -36,7 +36,7 @@ If you see just the first two lines and not the third one, please make sure that
 {
     "scripts": {
         "post-autoload-dump": [
-            "Pico\\Composer\\Installer\\PluginInstaller::postAutoloadDump"
+            "picocms\\ComposerInstaller\\Installer::postAutoloadDump"
         ]
     }
 }
diff --git a/composer.json b/composer.json
index 869aa10..6b5df51 100644
--- a/composer.json
+++ b/composer.json
@@ -1,9 +1,9 @@
 {
     "name": "picocms/composer-installer",
-    "type": "composer-installer",
+    "type": "composer-plugin",
     "description": "A composer plugin responsible for installing plugins and themes for Pico, a stupidly simple, blazing fast, flat file CMS.",
     "keywords": [ "pico", "picocms", "pico-cms", "picocms-plugin", "picocms-theme", "picocms-installer", "composer", "composer-plugin", "composer-installer" ],
-    "homepage": "http://picocms.org/",
+    "homepage": "https://picocms.org/",
     "license": "MIT",
     "authors": [
         {
@@ -13,7 +13,7 @@
         },
         {
             "name": "The Pico Community",
-            "homepage": "http://picocms.org/"
+            "homepage": "https://picocms.org/"
         },
         {
             "name": "Contributors",
@@ -24,12 +24,20 @@
         "issues": "https://github.com/picocms/composer-installer/issues",
         "source": "https://github.com/picocms/composer-installer"
     },
+    "require": {
+        "php": ">=7.2",
+        "composer-plugin-api": "^2.1"
+    },
     "autoload": {
         "psr-4": {
-            "Pico\\Composer\\": "src"
+            "picocms\\ComposerInstaller\\": "src"
         }
     },
     "extra": {
-        "class": "Pico\\Composer\\Installer\\PluginInstaller"
+        "class": "picocms\\ComposerInstaller\\Plugin",
+        "branch-alias": {
+            "dev-master": "1.0.x-dev",
+            "dev-pico-3.0": "2.0.x-dev"
+        }
     }
 }
diff --git a/src/Installer/PluginInstaller.php b/src/Installer.php
similarity index 81%
rename from src/Installer/PluginInstaller.php
rename to src/Installer.php
index 7bc9aad..57f7504 100644
--- a/src/Installer/PluginInstaller.php
+++ b/src/Installer.php
@@ -4,13 +4,13 @@
  * in the version control history of the file, available from the following
  * original location:
  *
- * <https://github.com/picocms/composer-installer/blob/master/src/Installer/PluginInstaller.php>
+ * <https://github.com/picocms/composer-installer/blob/master/src/Installer.php>
  *
  * SPDX-License-Identifier: MIT
  * License-Filename: LICENSE
  */
 
-namespace Pico\Composer\Installer;
+namespace picocms\ComposerInstaller;
 
 use Composer\Composer;
 use Composer\Installer\BinaryInstaller;
@@ -18,6 +18,7 @@
 use Composer\IO\IOInterface;
 use Composer\Package\AliasPackage;
 use Composer\Package\PackageInterface;
+use Composer\Package\RootPackageInterface;
 use Composer\Script\Event;
 use Composer\Util\Filesystem;
 
@@ -28,40 +29,40 @@
  * and themes for Pico using Composer. Pico is a stupidly simple, blazing fast,
  * flat file CMS.
  *
- * See <http://picocms.org/> for more info.
+ * See <https://picocms.org/> for more info.
  *
  * @author  Daniel Rudolf
- * @link    http://picocms.org
- * @license http://opensource.org/licenses/MIT The MIT License
- * @version 1.0
+ * @link    https://picocms.org
+ * @license https://opensource.org/licenses/MIT The MIT License
+ * @version 2.0
  */
-class PluginInstaller extends LibraryInstaller
+class Installer extends LibraryInstaller
 {
     /**
      * Package name of this composer installer
      *
      * @var string
      */
-    const PACKAGE_NAME = 'picocms/composer-installer';
+    public const PACKAGE_NAME = 'picocms/composer-installer';
 
     /**
      * Package type of Pico plugins
      *
      * @var string
      */
-    const PACKAGE_TYPE_PLUGIN = 'pico-plugin';
+    public const PACKAGE_TYPE_PLUGIN = 'pico-plugin';
 
     /**
      * Package type of Pico themes
      *
      * @var string
      */
-    const PACKAGE_TYPE_THEME = 'pico-theme';
+    public const PACKAGE_TYPE_THEME = 'pico-theme';
 
     /**
      * Composer root package
      *
-     * @var PackageInterface|null
+     * @var RootPackageInterface|null
      */
     protected $rootPackage;
 
@@ -70,10 +71,10 @@ class PluginInstaller extends LibraryInstaller
      *
      * @var string[]
      */
-    protected $installDirs = array(
+    protected $installDirs = [
         self::PACKAGE_TYPE_PLUGIN => 'plugins',
-        self::PACKAGE_TYPE_THEME => 'themes'
-    );
+        self::PACKAGE_TYPE_THEME => 'themes',
+    ];
 
     /**
      * A flag to check usage of the postAutoloadDump event
@@ -86,38 +87,37 @@ class PluginInstaller extends LibraryInstaller
      * Initializes Pico plugin and theme installer
      *
      * This method tries to register the `post-autoload-dump` script
-     * ({@see PluginInstaller::postAutoloadDump()}), if it wasn't explicitly
+     * ({@see Installer::postAutoloadDump()}), if it wasn't explicitly
      * set already. If this isn't possible, the autoload dump event can't be
-     * used ({@see PluginInstaller::checkAutoloadDump()}).
+     * used ({@see Installer::checkAutoloadDump()}).
      *
-     * @param IOInterface     $io
-     * @param Composer        $composer
-     * @param string          $type
-     * @param Filesystem      $filesystem
-     * @param BinaryInstaller $binaryInstaller
+     * @param IOInterface          $io
+     * @param Composer             $composer
+     * @param string|null          $type
+     * @param Filesystem|null      $filesystem
+     * @param BinaryInstaller|null $binaryInstaller
      */
     public function __construct(
         IOInterface $io,
         Composer $composer,
-        $type = 'library',
-        Filesystem $filesystem = null,
-        BinaryInstaller $binaryInstaller = null
+        ?string $type = 'library',
+        ?Filesystem $filesystem = null,
+        ?BinaryInstaller $binaryInstaller = null
     ) {
         parent::__construct($io, $composer, $type, $filesystem, $binaryInstaller);
+
         $this->rootPackage = static::getRootPackage($this->composer);
 
         // try to register the `post-autoload-dump` script
         $scripts = $this->rootPackage->getScripts();
-        $callback = get_called_class() . '::postAutoloadDump';
+        $callback = static::class . '::postAutoloadDump';
         if (isset($scripts['post-autoload-dump']) && in_array($callback, $scripts['post-autoload-dump'])) {
             // the user explicitly added the `post-autoload-dump` script,
             // force the autoload dump event to be used
             static::$useAutoloadDump = true;
         } else {
-            if (is_callable(array($this->rootPackage, 'setScripts'))) {
-                $scripts['post-autoload-dump'][] = $callback;
-                $this->rootPackage->setScripts($scripts);
-            }
+            $scripts['post-autoload-dump'][] = $callback;
+            $this->rootPackage->setScripts($scripts);
 
             // check whether the autoload dump event is used
             static::checkAutoloadDump($this->composer);
@@ -129,7 +129,7 @@ public function __construct(
      *
      * Using the autoload dump event will always create `pico-plugin.php` in
      * Composer's vendor dir. Plugins are nevertheless installed to Pico's
-     * `plugins/` dir ({@see PluginInstaller::getInstallPath()}).
+     * `plugins/` dir ({@see Installer::getInstallPath()}).
      *
      * The autoload dump event is used when the root package is a project and
      * explicitly requires this composer installer.
@@ -138,23 +138,23 @@ public function __construct(
      *
      * @return bool
      */
-    public static function checkAutoloadDump(Composer $composer)
+    public static function checkAutoloadDump(Composer $composer): bool
     {
         if (static::$useAutoloadDump === null) {
             static::$useAutoloadDump = false;
 
             $rootPackage = static::getRootPackage($composer);
-            if (!$rootPackage || ($rootPackage->getType() !== 'project')) {
+            if ($rootPackage->getType() !== 'project') {
                 return false;
             }
 
             $rootPackageRequires = $rootPackage->getRequires();
-            if (!isset($rootPackageRequires[static::PACKAGE_NAME])) {
+            if (!isset($rootPackageRequires[self::PACKAGE_NAME])) {
                 return false;
             }
 
             $scripts = $rootPackage->getScripts();
-            $callback = get_called_class() . '::postAutoloadDump';
+            $callback = static::class . '::postAutoloadDump';
             if (!isset($scripts['post-autoload-dump']) || !in_array($callback, $scripts['post-autoload-dump'])) {
                 return false;
             }
@@ -173,7 +173,7 @@ public static function checkAutoloadDump(Composer $composer)
      *
      * @param Event $event
      */
-    public static function postAutoloadDump(Event $event)
+    public static function postAutoloadDump(Event $event): void
     {
         $io = $event->getIO();
         $composer = $event->getComposer();
@@ -201,9 +201,10 @@ public static function postAutoloadDump(Event $event)
         $rootPackage = static::getRootPackage($composer);
         $packages = $composer->getRepositoryManager()->getLocalRepository()->getPackages();
 
-        $plugins = $pluginClassNames = array();
+        $plugins = [];
+        $pluginClassNames = [];
         foreach ($packages as $package) {
-            if ($package->getType() !== static::PACKAGE_TYPE_PLUGIN) {
+            if ($package->getType() !== self::PACKAGE_TYPE_PLUGIN) {
                 continue;
             }
 
@@ -222,7 +223,7 @@ public static function postAutoloadDump(Event $event)
      * package's or the plugin package's `composer.json`, or are derived
      * implicitly from the plugin's installer name. The installer name is, for
      * its part, either specified explicitly, or derived implicitly from the
-     * plugin package's name ({@see PluginInstaller::getInstallName()}).
+     * plugin package's name ({@see Installer::getInstallName()}).
      *
      * 1. Using the "pico-plugin" extra in the root package's `composer.json`:
      *    ```yaml
@@ -236,7 +237,7 @@ public static function postAutoloadDump(Event $event)
      *    ```
      *
      *    Besides matching exact package names, you can also use the prefixes
-     *    `vendor:` or `name:` ({@see PluginInstaller::mapRootExtra()}).
+     *    `vendor:` or `name:` ({@see Installer::mapRootExtra()}).
      *
      * 2. Using the "pico-plugin" extra in the package's `composer.json`:
      *    ```yaml
@@ -247,19 +248,21 @@ public static function postAutoloadDump(Event $event)
      *    }
      *    ```
      *
-     * 3. Using the installer name ({@see PluginInstaller::getInstallName()}).
+     * 3. Using the installer name ({@see Installer::getInstallName()}).
      *
      * @param PackageInterface      $package
      * @param PackageInterface|null $rootPackage
      *
      * @return string[]
      */
-    public static function getPluginClassNames(PackageInterface $package, PackageInterface $rootPackage = null)
-    {
+    public static function getPluginClassNames(
+        PackageInterface $package,
+        ?PackageInterface $rootPackage = null
+    ): array {
         $packageType = $package->getType();
         $packagePrettyName = $package->getPrettyName();
 
-        $classNames = array();
+        $classNames = [];
 
         // 1. root package
         $rootPackageExtra = $rootPackage ? $rootPackage->getExtra() : null;
@@ -278,7 +281,7 @@ public static function getPluginClassNames(PackageInterface $package, PackageInt
         // 3. guess by installer name
         if (!$classNames) {
             $installName = static::getInstallName($package, $rootPackage);
-            $classNames = array($installName);
+            $classNames = [ $installName ];
         }
 
         return $classNames;
@@ -293,14 +296,14 @@ public static function getPluginClassNames(PackageInterface $package, PackageInt
      * name.
      *
      * Install names are determined the same way as plugin class names. See
-     * {@see PluginInstaller::getPluginClassNames()} for details.
+     * {@see Installer::getPluginClassNames()} for details.
      *
      * @param PackageInterface      $package
      * @param PackageInterface|null $rootPackage
      *
      * @return string
      */
-    public static function getInstallName(PackageInterface $package, PackageInterface $rootPackage = null)
+    public static function getInstallName(PackageInterface $package, ?PackageInterface $rootPackage = null): string
     {
         $packagePrettyName = $package->getPrettyName();
         $packageName = $package->getName();
@@ -332,11 +335,11 @@ public static function getInstallName(PackageInterface $package, PackageInterfac
      *
      * @return string
      */
-    protected static function guessInstallName($packageName)
+    protected static function guessInstallName(string $packageName): string
     {
         $name = $packageName;
         if (strpos($packageName, '/') !== false) {
-            list(, $name) = explode('/', $packageName);
+            [, $name] = explode('/', $packageName);
         }
 
         $name = preg_replace('/[\.\-_]+(?>plugin|theme)$/u', '', $name);
@@ -363,24 +366,28 @@ function ($matches) {
      *
      * @return mixed
      */
-    protected static function mapRootExtra(array $packageExtra, $packagePrettyName)
+    protected static function mapRootExtra(array $packageExtra, string $packagePrettyName)
     {
         if (isset($packageExtra[$packagePrettyName])) {
             return $packageExtra[$packagePrettyName];
         }
 
         if (strpos($packagePrettyName, '/') !== false) {
-            list($vendor, $name) = explode('/', $packagePrettyName);
+            [$vendor, $name] = explode('/', $packagePrettyName);
         } else {
             $vendor = '';
             $name = $packagePrettyName;
         }
 
         foreach ($packageExtra as $key => $value) {
-            if ((substr($key, 0, 5) === 'name:') && (substr($key, 5) === $name)) {
-                return $value;
-            } elseif ((substr($key, 0, 7) === 'vendor:') && (substr($key, 7) === $vendor)) {
-                return $value;
+            if (substr_compare($key, 'name:', 0, 5) === 0) {
+                if (substr_compare($key, $name, 5) === 0) {
+                    return $value;
+                }
+            } elseif (substr_compare($key, 'vendor:', 0, 7) === 0) {
+                if (substr_compare($key, $vendor, 7) === 0) {
+                    return $value;
+                }
             }
         }
 
@@ -394,9 +401,9 @@ protected static function mapRootExtra(array $packageExtra, $packagePrettyName)
      *
      * @return string
      */
-    protected static function getPluginConfig($vendorDir)
+    protected static function getPluginConfig(string $vendorDir): string
     {
-        return $vendorDir . '/' . static::PACKAGE_TYPE_PLUGIN . '.php';
+        return $vendorDir . '/pico-plugin.php';
     }
 
     /**
@@ -406,9 +413,9 @@ protected static function getPluginConfig($vendorDir)
      * @param array  $plugins
      * @param array  $pluginClassNames
      */
-    public static function writePluginConfig($pluginConfig, array $plugins, array $pluginClassNames)
+    public static function writePluginConfig(string $pluginConfig, array $plugins, array $pluginClassNames): void
     {
-        $data = array();
+        $data = [];
         foreach ($plugins as $pluginName => $installerName) {
             // see https://github.com/composer/composer/blob/1.0.0/src/Composer/Command/InitCommand.php#L206-L210
             if (!preg_match('{^[a-z0-9_.-]+/[a-z0-9_.-]+$}', $pluginName)) {
@@ -417,6 +424,7 @@ public static function writePluginConfig($pluginConfig, array $plugins, array $p
                     . "a forward slash, and a package name, matching: [a-z0-9_.-]+/[a-z0-9_.-]+"
                 );
             }
+
             $data[] = sprintf("    '%s' => array(", $pluginName);
 
             if (!preg_match('{^[a-zA-Z0-9_.-]+$}', $installerName)) {
@@ -425,6 +433,7 @@ public static function writePluginConfig($pluginConfig, array $plugins, array $p
                     . "it must be alphanumeric, matching: [a-zA-Z0-9_.-]+"
                 );
             }
+
             $data[] = sprintf("        'installerName' => '%s',", $installerName);
 
             if (isset($pluginClassNames[$pluginName])) {
@@ -437,6 +446,7 @@ public static function writePluginConfig($pluginConfig, array $plugins, array $p
                             "The plugin class name '" . $className . "' is no valid PHP class name"
                         );
                     }
+
                     $data[] = sprintf("            '%s',", $className);
                 }
 
@@ -460,7 +470,7 @@ public static function writePluginConfig($pluginConfig, array $plugins, array $p
         $contents = sprintf(
             $contents,
             basename($pluginConfig),
-            static::PACKAGE_NAME,
+            self::PACKAGE_NAME,
             implode("\n", $data)
         );
 
@@ -472,9 +482,9 @@ public static function writePluginConfig($pluginConfig, array $plugins, array $p
      *
      * @param Composer $composer
      *
-     * @return PackageInterface
+     * @return RootPackageInterface
      */
-    protected static function getRootPackage(Composer $composer)
+    protected static function getRootPackage(Composer $composer): RootPackageInterface
     {
         $rootPackage = $composer->getPackage();
         if ($rootPackage) {
@@ -496,8 +506,8 @@ protected static function getRootPackage(Composer $composer)
     public function supports($packageType)
     {
         return (
-            ($packageType === static::PACKAGE_TYPE_PLUGIN)
-            || ($packageType === static::PACKAGE_TYPE_THEME)
+            ($packageType === self::PACKAGE_TYPE_PLUGIN)
+            || ($packageType === self::PACKAGE_TYPE_THEME)
         );
     }
 
@@ -529,7 +539,7 @@ public function getInstallPath(PackageInterface $package)
      *
      * @return string
      */
-    protected function initializeInstallDir($packageType)
+    protected function initializeInstallDir(string $packageType): string
     {
         $installDir = '';
 
diff --git a/src/Plugin.php b/src/Plugin.php
new file mode 100644
index 0000000..d7394b6
--- /dev/null
+++ b/src/Plugin.php
@@ -0,0 +1,79 @@
+<?php
+/**
+ * This file is part of Pico. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from the following
+ * original location:
+ *
+ * <https://github.com/picocms/composer-installer/blob/master/src/Plugin.php>
+ *
+ * SPDX-License-Identifier: MIT
+ * License-Filename: LICENSE
+ */
+
+namespace picocms\ComposerInstaller;
+
+use Composer\Composer;
+use Composer\IO\IOInterface;
+use Composer\Plugin\PluginInterface;
+
+/**
+ * Composer plugin for the Pico plugin and theme installer
+ *
+ * This Composer plugin registers Pico's plugin and theme installer. Pico is a
+ * stupidly simple, blazing fast, flat file CMS.
+ *
+ * See <https://picocms.org/> for more info.
+ *
+ * @author  Daniel Rudolf
+ * @link    https://picocms.org
+ * @license https://opensource.org/licenses/MIT The MIT License
+ * @version 2.0
+ */
+class Plugin implements PluginInterface
+{
+    /**
+     * Instance of Pico's plugin and theme installer
+     *
+     * @var Installer|null
+     */
+    private $installer;
+
+    /**
+     * Adds Pico's plugin and theme installer to Composer
+     *
+     * @param Composer    $composer
+     * @param IOInterface $io
+     *
+     * @return void
+     */
+    public function activate(Composer $composer, IOInterface $io): void
+    {
+        $this->installer = new Installer($io, $composer);
+        $composer->getInstallationManager()->addInstaller($this->installer);
+    }
+
+    /**
+     * Removes Pico's plugin and theme installer from Composer
+     *
+     * @param Composer    $composer
+     * @param IOInterface $io
+     *
+     * @return void
+     */
+    public function deactivate(Composer $composer, IOInterface $io): void
+    {
+        $composer->getInstallationManager()->removeInstaller($this->installer);
+    }
+
+    /**
+     * Uninstalls the Composer plugin (no-op)
+     *
+     * @param Composer    $composer
+     * @param IOInterface $io
+     *
+     * @return void
+     */
+    public function uninstall(Composer $composer, IOInterface $io): void
+    {
+    }
+}