diff --git a/plugins/generic/announcementFeed/AnnouncementFeedGatewayPlugin.php b/plugins/generic/announcementFeed/AnnouncementFeedGatewayPlugin.php
index bf330fa94e3..3b243717214 100644
--- a/plugins/generic/announcementFeed/AnnouncementFeedGatewayPlugin.php
+++ b/plugins/generic/announcementFeed/AnnouncementFeedGatewayPlugin.php
@@ -20,6 +20,7 @@
 use PKP\announcement\Announcement;
 use PKP\db\DAORegistry;
 use PKP\facades\Locale;
+use PKP\i18n\LocaleConversion;
 use PKP\plugins\GatewayPlugin;
 use PKP\site\VersionDAO;
 
@@ -162,7 +163,7 @@ public function fetch($args, $request)
             'dateUpdated' => $dateUpdated,
             'announcements' => $announcements,
             'journal' => $journal,
-            'language' => str_replace(['_', '@'], '-', Locale::getLocale()),
+            'language' => LocaleConversion::toBcp47(Locale::getLocale()),
         ]);
 
         $templateMgr->setHeaders(['content-type: ' . $mimeTypeMap[$type] . '; charset=utf-8']);
diff --git a/plugins/generic/datacite/filter/DataciteXmlFilter.php b/plugins/generic/datacite/filter/DataciteXmlFilter.php
index 6c413091810..08fb5bfe3b2 100644
--- a/plugins/generic/datacite/filter/DataciteXmlFilter.php
+++ b/plugins/generic/datacite/filter/DataciteXmlFilter.php
@@ -214,7 +214,7 @@ public function &process(&$pubObject): DOMDocument
         // Dates
         $rootNode->appendChild($this->createDatesNode($doc, $issue, $article, $publication, $galleyFile, $publicationDate));
         // Language
-        $rootNode->appendChild($node = $doc->createElementNS($deployment->getNamespace(), 'language', str_replace(['_', '@'], '-', $objectLocalePrecedence[0])));
+        $rootNode->appendChild($node = $doc->createElementNS($deployment->getNamespace(), 'language', LocaleConversion::toBcp47($objectLocalePrecedence[0])));
         // Resource Type
         $resourceTypeNode = $this->createResourceTypeNode($doc, $issue, $article, $galley, $galleyFile);
         if ($resourceTypeNode) {
diff --git a/plugins/generic/dublinCoreMeta/DublinCoreMetaPlugin.php b/plugins/generic/dublinCoreMeta/DublinCoreMetaPlugin.php
index 49a75b2092e..eb2fa6cd11b 100644
--- a/plugins/generic/dublinCoreMeta/DublinCoreMetaPlugin.php
+++ b/plugins/generic/dublinCoreMeta/DublinCoreMetaPlugin.php
@@ -17,6 +17,7 @@
 use APP\facades\Repo;
 use APP\template\TemplateManager;
 use PKP\core\PKPApplication;
+use PKP\i18n\LocaleConversion;
 use PKP\plugins\GenericPlugin;
 use PKP\plugins\Hook;
 
@@ -83,7 +84,7 @@ public function articleView($hookName, $args)
         if ($supportingAgencies = $publication->getData('supportingAgencies')) {
             foreach ($supportingAgencies as $locale => $localeSupportingAgencies) {
                 foreach ($localeSupportingAgencies as $i => $supportingAgency) {
-                    $templateMgr->addHeader('dublinCoreSponsor' . $locale . $i++, '<meta name="DC.Contributor.Sponsor" xml:lang="' . htmlspecialchars(str_replace(['_', '@'], '-', $locale)) . '" content="' . htmlspecialchars($supportingAgency) . '"/>');
+                    $templateMgr->addHeader('dublinCoreSponsor' . $locale . $i++, '<meta name="DC.Contributor.Sponsor" xml:lang="' . htmlspecialchars(LocaleConversion::toBcp47($locale)) . '" content="' . htmlspecialchars($supportingAgency) . '"/>');
                 }
             }
         }
@@ -91,7 +92,7 @@ public function articleView($hookName, $args)
         if ($coverages = $publication->getData('coverage')) {
             foreach ($coverages as $locale => $coverage) {
                 if ($coverage != '') {
-                    $templateMgr->addHeader('dublinCoreCoverage' . $locale, '<meta name="DC.Coverage" xml:lang="' . htmlspecialchars(str_replace(['_', '@'], '-', $locale)) . '" content="' . htmlspecialchars(strip_tags($coverage)) . '"/>');
+                    $templateMgr->addHeader('dublinCoreCoverage' . $locale, '<meta name="DC.Coverage" xml:lang="' . htmlspecialchars(LocaleConversion::toBcp47($locale)) . '" content="' . htmlspecialchars(strip_tags($coverage)) . '"/>');
                 }
             }
         }
@@ -115,7 +116,7 @@ public function articleView($hookName, $args)
         $abstracts = $publication->getData('abstract') ?: [];
         foreach ($abstracts as $locale => $abstract) {
             if ($abstract != '') {
-                $templateMgr->addHeader('dublinCoreAbstract' . $locale, '<meta name="DC.Description" xml:lang="' . htmlspecialchars(str_replace(['_', '@'], '-', $locale)) . '" content="' . htmlspecialchars(strip_tags($abstract)) . '"/>');
+                $templateMgr->addHeader('dublinCoreAbstract' . $locale, '<meta name="DC.Description" xml:lang="' . htmlspecialchars(LocaleConversion::toBcp47($locale)) . '" content="' . htmlspecialchars(strip_tags($abstract)) . '"/>');
             }
         }
 
@@ -146,7 +147,7 @@ public function articleView($hookName, $args)
 
         $templateMgr->addHeader('dublinCoreUri', '<meta name="DC.Identifier.URI" content="' . $request->getDispatcher()->url($request, PKPApplication::ROUTE_PAGE, null, 'article', 'view', [$articleBestId], urlLocaleForPage: '') . '"/>');
 
-        $templateMgr->addHeader('dublinCoreLanguage', '<meta name="DC.Language" scheme="rfc5646" content="' . str_replace(['_', '@'], '-', $publicationLocale) . '"/>');
+        $templateMgr->addHeader('dublinCoreLanguage', '<meta name="DC.Language" scheme="rfc5646" content="' . LocaleConversion::toBcp47($publicationLocale) . '"/>');
 
         if (($copyrightHolder = $publication->getData('copyrightHolder', $publicationLocale)) && ($copyrightYear = $publication->getData('copyrightYear'))) {
             $templateMgr->addHeader('dublinCoreCopyright', '<meta name="DC.Rights" content="' . htmlspecialchars(__('submission.copyrightStatement', ['copyrightHolder' => $copyrightHolder, 'copyrightYear' => $copyrightYear])) . '"/>');
@@ -172,14 +173,14 @@ public function articleView($hookName, $args)
         if ($subjects = $publication->getData('subjects')) {
             foreach ($subjects as $locale => $localeSubjects) {
                 foreach ($localeSubjects as $i => $subject) {
-                    $templateMgr->addHeader('dublinCoreSubject' . $locale . $i++, '<meta name="DC.Subject" xml:lang="' . htmlspecialchars(str_replace(['_', '@'], '-', $locale)) . '" content="' . htmlspecialchars($subject) . '"/>');
+                    $templateMgr->addHeader('dublinCoreSubject' . $locale . $i++, '<meta name="DC.Subject" xml:lang="' . htmlspecialchars(LocaleConversion::toBcp47($locale)) . '" content="' . htmlspecialchars($subject) . '"/>');
                 }
             }
         }
         if ($keywords = $publication->getData('keywords')) {
             foreach ($keywords as $locale => $localeKeywords) {
                 foreach ($localeKeywords as $i => $keyword) {
-                    $templateMgr->addHeader('dublinCoreKeyword' . $locale . $i++, '<meta name="DC.Subject" xml:lang="' . htmlspecialchars(str_replace(['_', '@'], '-', $locale)) . '" content="' . htmlspecialchars($keyword) . '"/>');
+                    $templateMgr->addHeader('dublinCoreKeyword' . $locale . $i++, '<meta name="DC.Subject" xml:lang="' . htmlspecialchars(LocaleConversion::toBcp47($locale)) . '" content="' . htmlspecialchars($keyword) . '"/>');
                 }
             }
         }
@@ -187,7 +188,7 @@ public function articleView($hookName, $args)
         $templateMgr->addHeader('dublinCoreTitle', '<meta name="DC.Title" content="' . htmlspecialchars($publication->getLocalizedFullTitle($publicationLocale)) . '"/>');
         foreach ($publication->getFullTitles() as $locale => $title) {
             if ($title != '' && $locale != $publicationLocale) {
-                $templateMgr->addHeader('dublinCoreAltTitle' . $locale, '<meta name="DC.Title.Alternative" xml:lang="' . htmlspecialchars(str_replace(['_', '@'], '-', $locale)) . '" content="' . htmlspecialchars($title) . '"/>');
+                $templateMgr->addHeader('dublinCoreAltTitle' . $locale, '<meta name="DC.Title.Alternative" xml:lang="' . htmlspecialchars(LocaleConversion::toBcp47($locale)) . '" content="' . htmlspecialchars($title) . '"/>');
             }
         }
 
@@ -195,7 +196,7 @@ public function articleView($hookName, $args)
         if ($types = $publication->getData('type')) {
             foreach ($types as $locale => $type) {
                 if ($type != '') {
-                    $templateMgr->addHeader('dublinCoreType' . $locale, '<meta name="DC.Type" xml:lang="' . htmlspecialchars(str_replace(['_', '@'], '-', $locale)) . '" content="' . htmlspecialchars(strip_tags($type)) . '"/>');
+                    $templateMgr->addHeader('dublinCoreType' . $locale, '<meta name="DC.Type" xml:lang="' . htmlspecialchars(LocaleConversion::toBcp47($locale)) . '" content="' . htmlspecialchars(strip_tags($type)) . '"/>');
                 }
             }
         }