diff --git a/pos/static/js/i18n.js b/pos/static/js/i18n.js
index ed28ee4..694a0f4 100644
--- a/pos/static/js/i18n.js
+++ b/pos/static/js/i18n.js
@@ -317,7 +317,9 @@ var I18N = {
   }
 };
 
-var currentLang = localStorage.getItem('pos_lang') || 'es';
+// Spanish is mandatory for all tenants; ignore any previously stored language.
+var currentLang = 'es';
+localStorage.setItem('pos_lang', 'es');
 
 /**
  * Translate a key to the current language.
@@ -328,12 +330,11 @@ window.t = function(key) {
 };
 
 /**
- * Switch the UI language and reload.
+ * Language switcher is disabled; the system stays in Spanish.
  */
 window.setLang = function(lang) {
-  currentLang = lang;
-  localStorage.setItem('pos_lang', lang);
-  location.reload();
+  currentLang = 'es';
+  localStorage.setItem('pos_lang', 'es');
 };
 
 /**
diff --git a/pos/static/js/sidebar.js b/pos/static/js/sidebar.js
index 8614798..c998174 100644
--- a/pos/static/js/sidebar.js
+++ b/pos/static/js/sidebar.js
@@ -15,7 +15,6 @@ window.renderSidebar = function(modulesOverride) {
     var initials = u.initials || '?';
     var currentPath = window.location.pathname;
     var currentTheme = localStorage.getItem('pos_theme') || 'industrial';
-    var currentLang = localStorage.getItem('pos_lang') || 'es';
 
     var modules = {};
     if (modulesOverride && typeof modulesOverride === 'object') {
@@ -104,16 +103,6 @@ window.renderSidebar = function(modulesOverride) {
         + '</button>'
         + '</div>';
 
-    // Language toggle buttons
-    var langHtml = '<div class="sidebar__lang-toggle">'
-        + '<button class="lang-toggle-btn' + (currentLang === 'es' ? ' is-active' : '') + '" onclick="setLang(\'es\')" title="Espanol">'
-        + '<span class="lang-flag">MX</span> ES'
-        + '</button>'
-        + '<button class="lang-toggle-btn' + (currentLang === 'en' ? ' is-active' : '') + '" onclick="setLang(\'en\')" title="English">'
-        + '<span class="lang-flag">US</span> EN'
-        + '</button>'
-        + '</div>';
-
     window.updateThemeButtons = function() {
         var t = localStorage.getItem('pos_theme') || 'industrial';
         document.querySelectorAll('.theme-toggle-btn').forEach(function(b, i) {
@@ -131,7 +120,6 @@ window.renderSidebar = function(modulesOverride) {
         + '</div>'
         + '<nav class="sidebar__nav">' + navHtml + '</nav>'
         + themeHtml
-        + langHtml
         + '<div class="sidebar__footer">'
         + '  <div class="sidebar__user-avatar">' + initials + '</div>'
         + '  <div class="sidebar__user-info">'
diff --git a/pos/templates/accounting.html b/pos/templates/accounting.html
index 4a0b754..b6a089e 100644
--- a/pos/templates/accounting.html
+++ b/pos/templates/accounting.html
@@ -492,11 +492,11 @@
     </div>
   </div>
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/accounting.v9.js?v=33" defer></script>
   <script src="/pos/static/js/sync-engine.js" defer></script>
   <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>
diff --git a/pos/templates/catalog.html b/pos/templates/catalog.html
index b5416ab..9bbdc4e 100644
--- a/pos/templates/catalog.html
+++ b/pos/templates/catalog.html
@@ -314,12 +314,12 @@
     </div>
   </div>
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/kiosk.js" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/catalog.js?v=33" defer></script>
   <script src="/pos/static/js/offline-banner.js" defer></script>
   <script src="/pos/static/js/chat.js" defer></script>
diff --git a/pos/templates/config.html b/pos/templates/config.html
index 864e274..ab12c64 100644
--- a/pos/templates/config.html
+++ b/pos/templates/config.html
@@ -922,11 +922,11 @@
     </div>
   </div>
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/kiosk.js" defer></script>
   <script src="/pos/static/js/config.js?v=35" defer></script>
   <script src="/pos/static/js/sync-engine.js" defer></script>
diff --git a/pos/templates/customers.html b/pos/templates/customers.html
index 604d211..39e5b6c 100644
--- a/pos/templates/customers.html
+++ b/pos/templates/customers.html
@@ -633,11 +633,11 @@
     </div>
   </div>
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/virtual-scroll.js" defer></script>
   <script src="/pos/static/js/customers.js?v=33" defer></script>
   <script src="/pos/static/js/offline-banner.js" defer></script>
diff --git a/pos/templates/dashboard.html b/pos/templates/dashboard.html
index bd83d50..dd02d09 100644
--- a/pos/templates/dashboard.html
+++ b/pos/templates/dashboard.html
@@ -595,11 +595,11 @@
 
 
   <script src="/pos/static/js/chart.umd.min.js" defer></script>
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/dashboard-stats.js?v=33" defer></script>
   <script src="/pos/static/js/dashboard.js?v=33" defer></script>
   <script src="/pos/static/js/sync-engine.js" defer></script>
diff --git a/pos/templates/diagrams.html b/pos/templates/diagrams.html
index d9fc58f..58018b1 100644
--- a/pos/templates/diagrams.html
+++ b/pos/templates/diagrams.html
@@ -148,12 +148,12 @@
     </main>
   </div>
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/kiosk.js" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/diagrams.js" defer></script>
   <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>
   <script src="/pos/static/js/pwa-install.js" defer></script>
diff --git a/pos/templates/fleet.html b/pos/templates/fleet.html
index cc3a573..be439a0 100644
--- a/pos/templates/fleet.html
+++ b/pos/templates/fleet.html
@@ -302,11 +302,11 @@
   </div>
 </div>
 
-<script src="/pos/static/js/i18n.js" defer></script>
+<script src="/pos/static/js/i18n.js?v=36" defer></script>
 <script src="/pos/static/js/app-init.js" defer></script>
 <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
 <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
 <script src="/pos/static/js/fleet.js" defer></script>
 <script src="/pos/static/js/offline-banner.js" defer></script>
 <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>
diff --git a/pos/templates/inventory.html b/pos/templates/inventory.html
index 28bf9c3..3967057 100644
--- a/pos/templates/inventory.html
+++ b/pos/templates/inventory.html
@@ -1052,11 +1052,11 @@
     <button class="banner__dismiss" onclick="document.getElementById('offlineBanner').style.display='none'" aria-label="Cerrar">&times;</button>
   </div>
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/virtual-scroll.js?v=33" defer></script>
   <script src="/pos/static/js/inventory.js?v=33" defer></script>
   <script src="/pos/static/js/offline-banner.js" defer></script>
diff --git a/pos/templates/invoicing.html b/pos/templates/invoicing.html
index 0e1ad87..9beb5fd 100644
--- a/pos/templates/invoicing.html
+++ b/pos/templates/invoicing.html
@@ -1063,11 +1063,11 @@
     </div>
   </div>
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/invoicing.js?v=33" defer></script>
   <script src="/pos/static/js/sync-engine.js" defer></script>
   <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>
diff --git a/pos/templates/marketplace_external.html b/pos/templates/marketplace_external.html
index 1fbb579..987da8e 100644
--- a/pos/templates/marketplace_external.html
+++ b/pos/templates/marketplace_external.html
@@ -342,11 +342,11 @@
     </div>
   </div>
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/marketplace_external.js?v=33" defer></script>
   <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>
 </body>
diff --git a/pos/templates/pos.html b/pos/templates/pos.html
index 68fe1e0..36d366b 100644
--- a/pos/templates/pos.html
+++ b/pos/templates/pos.html
@@ -613,7 +613,7 @@
   <!-- ================================================================
        JAVASCRIPT
        ================================================================ -->
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/kiosk.js" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
diff --git a/pos/templates/quotations.html b/pos/templates/quotations.html
index de6318b..f3d2d96 100644
--- a/pos/templates/quotations.html
+++ b/pos/templates/quotations.html
@@ -14,10 +14,10 @@
   <link rel="stylesheet" href="/pos/static/css/quotations.css"></head>
 <body>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
 
   <div class="page">
     <h1 class="page-title">Cotizaciones</h1>
diff --git a/pos/templates/reports.html b/pos/templates/reports.html
index ec4e66c..4479a8d 100644
--- a/pos/templates/reports.html
+++ b/pos/templates/reports.html
@@ -365,11 +365,11 @@
   </div>
   <!-- End app-shell -->
 
-  <script src="/pos/static/js/i18n.js" defer></script>
+  <script src="/pos/static/js/i18n.js?v=36" defer></script>
   <script src="/pos/static/js/app-init.js" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/reports.js?v=33" defer></script>
   <script src="/pos/static/js/sync-engine.js" defer></script>
   <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>
diff --git a/pos/templates/supplier_catalog.html b/pos/templates/supplier_catalog.html
index 86a7737..3a4395e 100644
--- a/pos/templates/supplier_catalog.html
+++ b/pos/templates/supplier_catalog.html
@@ -127,7 +127,7 @@
   </div>
 
   <script src="/pos/static/js/app-init.js" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
   <script src="/pos/static/js/supplier_catalog.js?v=33" defer></script>
   <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>
 </body>
diff --git a/pos/templates/whatsapp.html b/pos/templates/whatsapp.html
index a23f0fe..6a3b20b 100644
--- a/pos/templates/whatsapp.html
+++ b/pos/templates/whatsapp.html
@@ -131,12 +131,12 @@ function posLogout(){localStorage.removeItem('pos_token');window.location.href='
 </script>
 
 <!-- Sidebar -->
-<script src="/pos/static/js/i18n.js" defer></script>
+<script src="/pos/static/js/i18n.js?v=36" defer></script>
 <script src="/pos/static/js/app-init.js" defer></script>
 <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
 <script src="/pos/static/js/whatsapp2.js?v=33" defer></script>
 <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
 
   <script src="/pos/static/js/chat.js" defer></script>
 </body>
diff --git a/pos/templates/workshop.html b/pos/templates/workshop.html
index e56ac24..8f6318f 100644
--- a/pos/templates/workshop.html
+++ b/pos/templates/workshop.html
@@ -294,11 +294,11 @@
   </div>
 </div>
 
-<script src="/pos/static/js/i18n.js" defer></script>
+<script src="/pos/static/js/i18n.js?v=36" defer></script>
 <script src="/pos/static/js/app-init.js" defer></script>
 <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
 <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-<script src="/pos/static/js/sidebar.js?v=33" defer></script>
+<script src="/pos/static/js/sidebar.js?v=36" defer></script>
 <script src="/pos/static/js/offline-banner.js" defer></script>
 <script src="/pos/static/js/workshop.js?v=35" defer></script>
 <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>