diff --git a/_extensions/s2_latex/functions.php b/_extensions/s2_latex/functions.php
index e47db339..d8859df7 100644
--- a/_extensions/s2_latex/functions.php
+++ b/_extensions/s2_latex/functions.php
@@ -12,16 +12,16 @@
     die;
 }
 
-function s2_encodeURIComponent($str)
+function s2_encodeURIComponent(string $str): string
 {
     $revert = array('%21' => '!', '%2A' => '*', '%27' => "'", '%28' => '(', '%29' => ')');
     return strtr(rawurlencode($str), $revert);
 }
 
-function s2_latex_make($text)
+function s2_latex_make($text): string
 {
-    return preg_replace_callback('#\\$\\$([^<>\\$]*)\\$\\$#Ss', function ($matches) {
-        $formula = str_replace(array('&nbsp;', '&lt;', '&gt;', '&amp;'), array(' ', '<', '>', '&'), $matches[1]);
-        return '<img border="0" style="vertical-align: middle;" src="//i.upmath.me/png/' . s2_htmlencode(s2_encodeURIComponent($formula)) . '" alt="' . s2_htmlencode($formula) . '" />';
+    return preg_replace_callback('#\\$\\$([^<$]*)\\$\\$#S', static function ($matches) {
+        $formula = str_replace(['&nbsp;', '&lt;', '&gt;', '&amp;'], [' ', '<', '>', '&'], $matches[1]);
+        return '<img border="0" style="vertical-align: middle;" src="//i.upmath.me/svg/' . s2_htmlencode(s2_encodeURIComponent($formula)) . '" alt="' . s2_htmlencode($formula) . '" />';
     }, $text);
 }
diff --git a/_extensions/s2_latex/hooks/fn_get_template_pre_includes_merge.php b/_extensions/s2_latex/hooks/fn_get_template_pre_includes_merge.php
index 46c8c038..04c9ca28 100644
--- a/_extensions/s2_latex/hooks/fn_get_template_pre_includes_merge.php
+++ b/_extensions/s2_latex/hooks/fn_get_template_pre_includes_merge.php
@@ -6,11 +6,13 @@
  * @license http://www.gnu.org/licenses/gpl.html GPL version 2 or higher
  * @package s2_latex
  *
- * @var \S2\Cms\Asset\AssetPack $assetPack
+ * @var AssetPack $assetPack
  */
 
+use S2\Cms\Asset\AssetPack;
+
 if (!defined('S2_ROOT')) {
     die;
 }
 
-$assetPack->addHeadJs('//i.upmath.me/latex.js');
+$assetPack->addJs('//i.upmath.me/latex.js', [AssetPack::OPTION_PRELOAD, AssetPack::OPTION_DEFER]);
diff --git a/_extensions/s2_latex/hooks/pr_render_pre_get_content_4.php b/_extensions/s2_latex/hooks/pr_render_pre_get_content_4.php
index 255277fc..5ffae5df 100644
--- a/_extensions/s2_latex/hooks/pr_render_pre_get_content_4.php
+++ b/_extensions/s2_latex/hooks/pr_render_pre_get_content_4.php
@@ -7,11 +7,11 @@
  * @package s2_latex
  */
 
- if (!defined('S2_ROOT')) {
-     die;
+if (!defined('S2_ROOT')) {
+    die;
 }
 
-require S2_ROOT.'/_extensions/s2_latex'.'/functions.php';
+require S2_ROOT . '/_extensions/s2_latex/functions.php';
 
-$content['rss_title'] = s2_latex_make($content['rss_title']);
+$content['rss_title']       = s2_latex_make($content['rss_title']);
 $content['rss_description'] = s2_latex_make($content['rss_description']);
diff --git a/_extensions/s2_latex/hooks/pr_render_pre_item_render_4.php b/_extensions/s2_latex/hooks/pr_render_pre_item_render_4.php
index 8e55a0d0..90cded99 100644
--- a/_extensions/s2_latex/hooks/pr_render_pre_item_render_4.php
+++ b/_extensions/s2_latex/hooks/pr_render_pre_item_render_4.php
@@ -7,9 +7,9 @@
  * @package s2_latex
  */
 
- if (!defined('S2_ROOT')) {
-     die;
+if (!defined('S2_ROOT')) {
+    die;
 }
 
 $item['title'] = s2_latex_make($item['title']);
-$item['text'] = s2_latex_make($item['text']);
+$item['text']  = s2_latex_make($item['text']);
diff --git a/_extensions/s2_latex/lang/English.php b/_extensions/s2_latex/lang/English.php
index 1421b20b..01d61500 100644
--- a/_extensions/s2_latex/lang/English.php
+++ b/_extensions/s2_latex/lang/English.php
@@ -1,7 +1,7 @@
 <?php
 
-return array(
+return [
 
-	'Comment syntax' => 'Latex formulae: <span>$$</span>f(x) = x^2-\sqrt{x}<span>$$</span> converts into $$f(x) = x^2-\sqrt{x}$$.<br />',
+    'Comment syntax' => 'Latex formulas: <span>$$</span>f(x) = x^2-\sqrt{x}<span>$$</span> converts into $$f(x) = x^2-\sqrt{x}$$.<br />',
 
-);
+];
diff --git a/_extensions/s2_latex/manifest.xml b/_extensions/s2_latex/manifest.xml
index ac51f0b5..adc444af 100644
--- a/_extensions/s2_latex/manifest.xml
+++ b/_extensions/s2_latex/manifest.xml
@@ -4,9 +4,9 @@
 /**
  * LaTeX
  *
- * Integrates site with tex.s2cms.ru service
+ * Integrates site with i.upmath.me service
  *
- * @copyright (C) 2011-2014 Roman Parpalak
+ * @copyright (C) 2011-2023 Roman Parpalak
  * @license http://www.gnu.org/licenses/gpl.html GPL version 2 or higher
  * @package s2_latex
  */
@@ -16,7 +16,7 @@
 	<id>s2_latex</id>
 	<title>LaTeX</title>
 	<version>2.0dev</version>
-	<description>Allows to write LaTeX formulae.</description>
+	<description>Allows to write LaTeX formulas.</description>
 	<author>Roman Parpalak</author>
 
 	<minversion>2.0dev</minversion>