diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58201a8..ae06306 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,12 @@
+# v4.2.2
+## 03/04/2020
+
+1. [](#improved)
+    * Added second `$options` parameter to `ShortcodeCore->registerAllShortcodes()`, key `ignore` can be used to ignore class names / files from being loaded
+1. [](#bugfix)
+    * Fix shortcodes which do not override `init()` method, added deprecation notice instead [#82](https://github.com/getgrav/grav-plugin-shortcode-core/issues/82)
+    * Fixed error message showing up when updating older versions (<4.2.0) of the plugin [#84](https://github.com/getgrav/grav-plugin-shortcode-core/issues/84)
+
 # v4.2.1
 ## 02/14/2020
 
diff --git a/blueprints.yaml b/blueprints.yaml
index c7e5664..2231d25 100644
--- a/blueprints.yaml
+++ b/blueprints.yaml
@@ -1,5 +1,5 @@
 name: Shortcode Core
-version: 4.2.1
+version: 4.2.2
 description: "This plugin provides the core functionality for shortcode plugins"
 icon: code
 author:
diff --git a/classes/Shortcode.php b/classes/Shortcode.php
new file mode 100644
index 0000000..10cd16f
--- /dev/null
+++ b/classes/Shortcode.php
@@ -0,0 +1,7 @@
+<?php
+
+// This file is for older Grav versions (needed during plugin update).
+
+if (!class_exists(\Grav\Plugin\Shortcodes\Shortcode::class, false)) {
+    require_once __DIR__ . '/shortcodes/Shortcode.php';
+}
diff --git a/classes/ShortcodeManager.php b/classes/ShortcodeManager.php
new file mode 100644
index 0000000..df2ecc8
--- /dev/null
+++ b/classes/ShortcodeManager.php
@@ -0,0 +1,15 @@
+<?php
+
+// This file is for older Grav versions (needed during plugin update).
+
+@trigger_error(
+     '\\Grav\\Plugin\\ShortcodeManager class is deprecated, use \\Grav\\Plugin\\ShortcodeCore\\ShortcodeManager instead',
+    E_USER_DEPRECATED
+);
+
+if (!class_exists(\Grav\Plugin\ShortcodeCore\ShortcodeManager::class, false)) {
+    require_once __DIR__ . '/plugin/ShortcodeManager.php';
+}
+
+// Create alias for the deprecated class.
+class_alias(\Grav\Plugin\ShortcodeCore\ShortcodeManager::class, \Grav\Plugin\ShortcodeManager::class);
\ No newline at end of file
diff --git a/classes/ShortcodeObject.php b/classes/ShortcodeObject.php
new file mode 100644
index 0000000..c9d143e
--- /dev/null
+++ b/classes/ShortcodeObject.php
@@ -0,0 +1,7 @@
+<?php
+
+// This file is for older Grav versions (needed during plugin update).
+
+if (!class_exists(\Grav\Plugin\ShortcodeCore\ShortcodeObject::class, false)) {
+    require_once __DIR__ . '/shortcodes/ShortcodeObject.php';
+}
\ No newline at end of file
diff --git a/classes/plugin/ShortcodeManager.php b/classes/plugin/ShortcodeManager.php
index 1e506b0..3bac6f1 100644
--- a/classes/plugin/ShortcodeManager.php
+++ b/classes/plugin/ShortcodeManager.php
@@ -198,13 +198,15 @@ public function registerShortcode($name, $directory = null)
 
     /**
      * register all files as shortcodes in a particular directory
-     * @param  string $directory directory where the shortcodes are located
+     * @param string $directory directory where the shortcodes are located
+     * @param array $options Extra options
      */
-    public function registerAllShortcodes($directory)
+    public function registerAllShortcodes($directory, array $options = [])
     {
         try {
+            $ignore = $options['ignore'] ?? [];
             foreach (new \DirectoryIterator($directory) as $file) {
-                if ($file->isDot()) {
+                if ($file->isDot() || \in_array($file->getBasename('.php'), $ignore, true)) {
                     continue;
                 }
                 $this->registerShortcode($file->getFilename(), $directory);
diff --git a/classes/shortcodes/Shortcode.php b/classes/shortcodes/Shortcode.php
index 69ff388..a3c9e30 100644
--- a/classes/shortcodes/Shortcode.php
+++ b/classes/shortcodes/Shortcode.php
@@ -36,7 +36,15 @@ public function __construct()
     /**
      * Initialize shortcode handler
      */
-    abstract public function init();
+    public function init()
+    {
+        user_error(__METHOD__ . '() method will be abstract in the future, please override it!', E_USER_DEPRECATED);
+
+        // FIXME: This code had to be put back because of some plugins do not properly initialize themselves.
+        $this->shortcode->getHandlers()->add('u', static function(ShortcodeInterface $shortcode) {
+            return $shortcode->getContent();
+        });
+    }
 
     /**
      * Returns the name of the class if required
diff --git a/shortcode-core.php b/shortcode-core.php
index de7ea16..8979049 100644
--- a/shortcode-core.php
+++ b/shortcode-core.php
@@ -103,6 +103,10 @@ public function onPageContentProcessed(Event $e)
         $this->processShortcodes($e['page'], 'processContent');
     }
 
+    /**
+     * @param PageInterface $page
+     * @param string $type
+     */
     protected function processShortcodes(PageInterface $page, $type = 'processContent') {
         $meta = [];
         $config = $this->mergeConfig($page);
@@ -141,6 +145,10 @@ protected function processShortcodes(PageInterface $page, $type = 'processConten
         }
     }
 
+    /**
+     * @param PageInterface $page
+     * @return \Grav\Common\Data\Data
+     */
     protected function getConfig(PageInterface $page)
     {
         $config = $this->mergeConfig($page);
@@ -200,7 +208,7 @@ public function onPageContent(Event $event)
      */
     public function onShortcodeHandlers()
     {
-        $this->shortcodes->registerAllShortcodes(__DIR__ . '/classes/shortcodes');
+        $this->shortcodes->registerAllShortcodes(__DIR__ . '/classes/shortcodes', ['ignore' => ['Shortcode', 'ShortcodeObject']]);
 
         // Add custom shortcodes directory if provided
         $custom_shortcodes = $this->config->get('plugins.shortcode-core.custom_shortcodes');
@@ -214,12 +222,7 @@ public function onShortcodeHandlers()
      */
     public function onTwigInitialized()
     {
-        $this->grav['twig']->twig()->addFilter(
-            new \Twig_SimpleFilter(
-                'shortcodes',
-                [$this->shortcodes, 'processShortcodes']
-            )
-        );
+        $this->grav['twig']->twig()->addFilter(new \Twig_SimpleFilter('shortcodes', [$this->shortcodes, 'processShortcodes']));
         $this->grav['twig']->twig_vars['shortcode'] = new ShortcodeTwigVar();
     }
 }