diff --git a/public/index.html b/public/index.html
index a9d13e9..2f16499 100644
--- a/public/index.html
+++ b/public/index.html
@@ -202,6 +202,11 @@
                         <span>&nbsp;&nbsp;-&nbsp;&nbsp;</span>
                         <span>(Catalan)</span>
                     </button>
+                    <button class="btn fw wrap" value="cs">
+                        <span>Čeština</span>
+                        <span>&nbsp;&nbsp;-&nbsp;&nbsp;</span>
+                        <span>(Czech)</span>
+                    </button>
                     <button class="btn fw wrap" value="da">
                         <span>Dansk</span>
                         <span>&nbsp;&nbsp;-&nbsp;&nbsp;</span>
@@ -285,6 +290,11 @@
                         <span>&nbsp;&nbsp;-&nbsp;&nbsp;</span>
                         <span>(Turkish)</span>
                     </button>
+                    <button class="btn fw wrap" value="uk">
+                        <span>Українська</span>
+                        <span>&nbsp;&nbsp;-&nbsp;&nbsp;</span>
+                        <span>(Ukrainian)</span>
+                    </button>
                     <button class="btn fw wrap" value="zh-CN">
                         <span>中文</span>
                         <span>&nbsp;&nbsp;-&nbsp;&nbsp;</span>
diff --git a/public/scripts/localization.js b/public/scripts/localization.js
index 72b3453..ca07a93 100644
--- a/public/scripts/localization.js
+++ b/public/scripts/localization.js
@@ -3,7 +3,7 @@ class Localization {
         Localization.$htmlRoot = document.querySelector('html');
 
         Localization.defaultLocale = "en";
-        Localization.supportedLocales = ["ar", "be", "ca", "da", "de", "en", "es", "fr", "he", "hu", "id", "it", "ja", "kn", "nb", "nl", "pl", "pt-BR", "ro", "ru", "tr", "zh-CN", "zh-TW"];
+        Localization.supportedLocales = ["ar", "be", "ca", "cs", "da", "de", "en", "es", "fr", "he", "hu", "id", "it", "ja", "kn", "nb", "nl", "pl", "pt-BR", "ro", "ru", "tr", "uk", "zh-CN", "zh-TW"];
         Localization.supportedLocalesRtl = ["ar", "he"];
 
         Localization.translations = {};
diff --git a/public/service-worker.js b/public/service-worker.js
index d758f1c..7f8cb3f 100644
--- a/public/service-worker.js
+++ b/public/service-worker.js
@@ -29,6 +29,7 @@ const relativePathsToCache = [
     'lang/ar.json',
     'lang/be.json',
     'lang/ca.json',
+    'lang/cs.json',
     'lang/da.json',
     'lang/de.json',
     'lang/en.json',
@@ -47,6 +48,7 @@ const relativePathsToCache = [
     'lang/ro.json',
     'lang/ru.json',
     'lang/tr.json',
+    'lang/uk.json',
     'lang/zh-CN.json',
     'lang/zh-TW.json'
 ];