diff --git a/OpenGraphPlugin.inc.php b/OpenGraphPlugin.inc.php
deleted file mode 100644
index 1986c12..0000000
--- a/OpenGraphPlugin.inc.php
+++ /dev/null
@@ -1,137 +0,0 @@
-<?php
-
-/**
- * @file OpenGraphPlugin.inc.php
- *
- * Copyright (c) 2014-2020 Simon Fraser University
- * Copyright (c) 2003-2020 John Willinsky
- * Distributed under the GNU GPL v3. For full terms see the file LICENSE.
- *
- * @class OpenGraphPlugin
- * @ingroup plugins_generic_openGraph
- *
- * @brief Inject Open Graph meta tags into submission views to facilitate indexing.
- */
-
-import('lib.pkp.classes.plugins.GenericPlugin');
-
-class OpenGraphPlugin extends GenericPlugin {
-	/**
-	 * @copydoc Plugin::register()
-	 */
-	function register($category, $path, $mainContextId = null) {
-		if (parent::register($category, $path, $mainContextId)) {
-			if ($this->getEnabled($mainContextId)) {
-				HookRegistry::register('ArticleHandler::view', array(&$this, 'submissionView'));
-				HookRegistry::register('PreprintHandler::view', array(&$this, 'submissionView'));
-				 HookRegistry::register('CatalogBookHandler::book',array(&$this, 'submissionView'));
-			}
-			return true;
-		}
-		return false;
-	}
-
-	/**
-	 * Get the name of the settings file to be installed on new context
-	 * creation.
-	 * @return string
-	 */
-	function getContextSpecificPluginSettingsFile() {
-		return $this->getPluginPath() . '/settings.xml';
-	}
-
-	/**
-	 * Inject Open Graph metadata into submission landing page view
-	 * @param $hookName string
-	 * @param $args array
-	 * @return boolean
-	 */
-	function submissionView($hookName, $args) {
-		$application = Application::get();
-		$applicationName = $application->getName();
-		$request = $args[0];
-		$context = $request->getContext();
-		if ($applicationName == "ops"){
-			$submission = $args[1];
-			$submissionPath = array('preprint', 'view');
-			$objectType = "article";
-		}
-		elseif ($applicationName == "omp"){
-			$submission = $args[1];
-			$submissionPath = array('catalog', 'book');
-			$objectType = "book";
-		}
-		else {
-			$issue = $args[1];
-			$submission = $args[2];
-			$submissionPath = array('article', 'view');
-			$objectType = "article";
-		}
-
-		$templateMgr = TemplateManager::getManager($request);
-		$templateMgr->addHeader('openGraphSiteName', '<meta name="og:site_name" content="' . htmlspecialchars($context->getName($context->getPrimaryLocale())) . '"/>');
-		$templateMgr->addHeader('openGraphObjectType', '<meta name="og:type" content="' . htmlspecialchars($objectType) . '"/>');
-		$templateMgr->addHeader('openGraphTitle', '<meta name="og:title" content="' . htmlspecialchars($submission->getFullTitle($submission->getLocale())) . '"/>');
-		if ($abstract = PKPString::html2text($submission->getAbstract($submission->getLocale()))) $templateMgr->addHeader('openGraphDescription', '<meta name="og:description" content="' . htmlspecialchars($abstract) . '"/>');
-		$templateMgr->addHeader('openGraphUrl', '<meta name="og:url" content="' . $request->url(null, $submissionPath[0], $submissionPath[1], array($submission->getBestId())) . '"/>');
-		if ($locale = $submission->getLocale()) $templateMgr->addHeader('openGraphLocale', '<meta name="og:locale" content="' . htmlspecialchars($locale) . '"/>');
-
-		$openGraphImage = "";
-		if ($contextPageHeaderLogo = $context->getLocalizedData('pageHeaderLogoImage')){
-			$openGraphImage = $templateMgr->getTemplateVars('publicFilesDir') . "/" . $contextPageHeaderLogo['uploadName'];
-		}
-		if ($issue && $issueCoverImage = $issue->getLocalizedCoverImageUrl()){
-			$openGraphImage = $issueCoverImage;
-		}
-		if ($submissionCoverImage = $submission->getCurrentPublication()->getLocalizedCoverImageUrl($submission->getData('contextId'))){
-			$openGraphImage = $submissionCoverImage;
-		}
-		$templateMgr->addHeader('openGraphImage', '<meta name="og:image" content="' . htmlspecialchars($openGraphImage) . '"/>');
-
-		if ($datePublished = $submission->getDatePublished()) { 
-			$openGraphDateName = $applicationName == "omp" ? "book:release_date" : "article:published_time";
-			$templateMgr->addHeader('openGraphDate', '<meta name="' . $openGraphDateName . '" content="' . strftime('%Y-%m-%d', strtotime($datePublished)) . '"/>');
-		}
-
-		if ($applicationName == "omp") { 
-			$publicationFormats = $submission->getCurrentPublication()->getData('publicationFormats');
-			foreach ($publicationFormats as $publicationFormat) {
-				$identificationCodes = $publicationFormat->getIdentificationCodes();
-				while ($identificationCode = $identificationCodes->next()) {
-					if ($identificationCode->getCode() == "02" || $identificationCode->getCode() == "15") {
-						$templateMgr->addHeader('openGraphBookIsbn', '<meta name="book:isbn" content="' . htmlspecialchars($identificationCode->getValue()) . '"/>');
-					}
-				}
-			}
-		}
-
-		$i=0;
-		$dao = DAORegistry::getDAO('SubmissionKeywordDAO');
-		$keywords = $dao->getKeywords($submission->getCurrentPublication()->getId(), array(AppLocale::getLocale()));
-		foreach ($keywords as $locale => $localeKeywords) {
-			foreach ($localeKeywords as $keyword) {
-				$templateMgr->addHeader('openGraphArticleTag' . $i++, '<meta name="' . $objectType . ':tag" content="' . htmlspecialchars($keyword) . '"/>');
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * Get the display name of this plugin
-	 * @return string
-	 */
-	function getDisplayName() {
-		return __('plugins.generic.openGraph.name');
-	}
-
-	/**
-	 * Get the description of this plugin
-	 * @return string
-	 */
-	function getDescription() {
-		return __('plugins.generic.openGraph.description');
-	}
-}
-
-
diff --git a/OpenGraphPlugin.php b/OpenGraphPlugin.php
new file mode 100644
index 0000000..591cc93
--- /dev/null
+++ b/OpenGraphPlugin.php
@@ -0,0 +1,151 @@
+<?php
+
+/**
+ * @file OpenGraphPlugin.inc.php
+ *
+ * Copyright (c) 2014-2020 Simon Fraser University
+ * Copyright (c) 2003-2020 John Willinsky
+ * Distributed under the GNU GPL v3. For full terms see the file LICENSE.
+ *
+ * @class OpenGraphPlugin
+ * @ingroup plugins_generic_openGraph
+ *
+ * @brief Inject Open Graph meta tags into submission views to facilitate indexing.
+ */
+
+namespace APP\plugins\generic\openGraph;
+
+use PKP\plugins\GenericPlugin;
+use PKP\plugins\Hook;
+use APP\core\Application;
+use APP\template\TemplateManager;
+use PKP\core\PKPString;
+use PKP\db\DAORegistry;
+use PKP\facades\Locale;
+
+class OpenGraphPlugin extends GenericPlugin
+{
+    /**
+     * @copydoc Plugin::register()
+     */
+    public function register($category, $path, $mainContextId = null)
+    {
+        if (parent::register($category, $path, $mainContextId)) {
+            if ($this->getEnabled($mainContextId)) {
+                Hook::add('ArticleHandler::view', array(&$this, 'submissionView'));
+                Hook::add('PreprintHandler::view', array(&$this, 'submissionView'));
+                Hook::add('CatalogBookHandler::book', array(&$this, 'submissionView'));
+            }
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Get the name of the settings file to be installed on new context
+     * creation.
+     * @return string
+     */
+    public function getContextSpecificPluginSettingsFile()
+    {
+        return $this->getPluginPath() . '/settings.xml';
+    }
+
+    /**
+     * Inject Open Graph metadata into submission landing page view
+     * @param $hookName string
+     * @param $args array
+     * @return boolean
+     */
+    public function submissionView($hookName, $args)
+    {
+        $application = Application::get();
+        $applicationName = $application->getName();
+        $request = $args[0];
+        $context = $request->getContext();
+        if ($applicationName == "ops") {
+            $submission = $args[1];
+            $submissionPath = array('preprint', 'view');
+            $objectType = "article";
+        } elseif ($applicationName == "omp") {
+            $submission = $args[1];
+            $submissionPath = array('catalog', 'book');
+            $objectType = "book";
+        } else {
+            $issue = $args[1];
+            $submission = $args[2];
+            $submissionPath = array('article', 'view');
+            $objectType = "article";
+        }
+
+        $templateMgr = TemplateManager::getManager($request);
+        $templateMgr->addHeader('openGraphSiteName', '<meta property="og:site_name" content="' . htmlspecialchars($context->getName($context->getPrimaryLocale())) . '"/>');
+        $templateMgr->addHeader('openGraphObjectType', '<meta property="og:type" content="' . htmlspecialchars($objectType) . '"/>');
+        $templateMgr->addHeader('openGraphTitle', '<meta property="og:title" content="' . htmlspecialchars($submission->getFullTitle($submission->getLocale())) . '"/>');
+        if ($abstract = PKPString::html2text($submission->getAbstract($submission->getLocale()))) {
+            $templateMgr->addHeader('openGraphDescription', '<meta property="description" property="og:description" content="' . htmlspecialchars($abstract) . '"/>');
+        }
+        $templateMgr->addHeader('openGraphUrl', '<meta property="og:url" content="' . $request->url(null, $submissionPath[0], $submissionPath[1], array($submission->getBestId())) . '"/>');
+        if ($locale = $submission->getLocale()) {
+            $templateMgr->addHeader('openGraphLocale', '<meta property="og:locale" content="' . htmlspecialchars($locale) . '"/>');
+        }
+
+        $openGraphImage = "";
+        if ($contextPageHeaderLogo = $context->getLocalizedData('pageHeaderLogoImage')) {
+            $openGraphImage = $templateMgr->getTemplateVars('publicFilesDir') . "/" . $contextPageHeaderLogo['uploadName'];
+        }
+        if ($issue && $issueCoverImage = $issue->getLocalizedCoverImageUrl()) {
+            $openGraphImage = $issueCoverImage;
+        }
+        if ($submissionCoverImage = $submission->getCurrentPublication()->getLocalizedCoverImageUrl($submission->getData('contextId'))) {
+            $openGraphImage = $submissionCoverImage;
+        }
+        $templateMgr->addHeader('openGraphImage', '<meta property="og:image" content="' . htmlspecialchars($openGraphImage) . '"/>');
+
+        if ($datePublished = $submission->getDatePublished()) {
+            $openGraphDateName = $applicationName == "omp" ? "book:release_date" : "article:published_time";
+            $templateMgr->addHeader('openGraphDate', '<meta property="' . $openGraphDateName . '" content="' . strftime('%Y-%m-%d', strtotime($datePublished)) . '"/>');
+        }
+
+        if ($applicationName == "omp") {
+            $publicationFormats = $submission->getCurrentPublication()->getData('publicationFormats');
+            foreach ($publicationFormats as $publicationFormat) {
+                $identificationCodes = $publicationFormat->getIdentificationCodes();
+                while ($identificationCode = $identificationCodes->next()) {
+                    if ($identificationCode->getCode() == "02" || $identificationCode->getCode() == "15") {
+                        $templateMgr->addHeader('openGraphBookIsbn', '<meta property="book:isbn" content="' . htmlspecialchars($identificationCode->getValue()) . '"/>');
+                    }
+                }
+            }
+        }
+
+        $i = 0;
+        $dao = DAORegistry::getDAO('SubmissionKeywordDAO');
+        $keywords = $dao->getKeywords($submission->getCurrentPublication()->getId(), array(Locale::getLocale()));
+        foreach ($keywords as $locale => $localeKeywords) {
+            foreach ($localeKeywords as $keyword) {
+                $templateMgr->addHeader('openGraphArticleTag' . $i++, '<meta property="' . $objectType . ':tag" content="' . htmlspecialchars($keyword) . '"/>');
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Get the display name of this plugin
+     * @return string
+     */
+    public function getDisplayName()
+    {
+        return __('plugins.generic.openGraph.name');
+    }
+
+    /**
+     * Get the description of this plugin
+     * @return string
+     */
+    public function getDescription()
+    {
+        return __('plugins.generic.openGraph.description');
+    }
+}
diff --git a/index.php b/index.php
deleted file mode 100644
index e1b6fd4..0000000
--- a/index.php
+++ /dev/null
@@ -1,23 +0,0 @@
-<?php
-
-/**
- * @defgroup plugins_generic_openGraph OpenGraph plugin
- */
-
-/**
- * @file plugins/generic/openGraph/index.php
- *
- * Copyright (c) 2014-2020 Simon Fraser University
- * Copyright (c) 2003-2020 John Willinsky
- * Distributed under the GNU GPL v3. For full terms see the file LICENSE.
- *
- * @ingroup plugins_generic_openGraph
- * @brief Wrapper for OpenGraph plugin.
- *
- */
-
-require_once('OpenGraphPlugin.inc.php');
-
-return new OpenGraphPlugin();
-
-
diff --git a/locale/en_US/locale.po b/locale/en/locale.po
similarity index 100%
rename from locale/en_US/locale.po
rename to locale/en/locale.po
diff --git a/locale/fi_FI/locale.po b/locale/fi/locale.po
similarity index 100%
rename from locale/fi_FI/locale.po
rename to locale/fi/locale.po
diff --git a/version.xml b/version.xml
index d850375..293ca75 100644
--- a/version.xml
+++ b/version.xml
@@ -15,6 +15,4 @@
 	<type>plugins.generic</type>
 	<release>1.0.1.0</release>
 	<date>2021-02-08</date>
-	<lazy-load>1</lazy-load>
-	<class>OpenGraphPlugin</class>
 </version>