diff --git a/gluon.json b/gluon.json
index 68f74b444..ebe5355ed 100644
--- a/gluon.json
+++ b/gluon.json
@@ -5,7 +5,7 @@
   "binaryName": "zen",
   "version": {
     "product": "firefox",
-    "version": "125.0.3",
+    "version": "126.0",
     "displayVersion": "1.0.0"
   },
   "buildOptions": {
diff --git a/src/browser/app/profile/firefox-js.patch b/src/browser/app/profile/firefox-js.patch
index cec24c263..015b89289 100644
--- a/src/browser/app/profile/firefox-js.patch
+++ b/src/browser/app/profile/firefox-js.patch
@@ -1,10 +1,10 @@
 diff --git a/browser/app/profile/firefox.js b/browser/app/profile/firefox.js
-index 1ef5a05907f4675e4e7191dde12c33dc6da5e3c6..69279a1a1278b7034df24b9763c5722a6c623bbc 100644
+index 8c4b0e28e53f3f0e0e492dd8f351535a5604af73..968c8792f4a2358da3f89cabfa179585bfbf0874 100644
 --- a/browser/app/profile/firefox.js
 +++ b/browser/app/profile/firefox.js
-@@ -3037,3 +3037,5 @@ pref("browser.profiles.enabled", false);
+@@ -3038,3 +3038,5 @@ pref("startup.homepage_override_nimbus_maxVersion", "");
  
- pref("startup.homepage_override_url_nimbus", "");
- pref("startup.homepage_override_nimbus_maxVersion", "");
+ // Pref to enable the content relevancy feature.
+ pref("toolkit.contentRelevancy.enabled", false);
 +
 +#include zen-browser.js
diff --git a/src/browser/base/content/aboutDialog-xhtml.patch b/src/browser/base/content/aboutDialog-xhtml.patch
index 231f3c727..4ed1133a6 100644
--- a/src/browser/base/content/aboutDialog-xhtml.patch
+++ b/src/browser/base/content/aboutDialog-xhtml.patch
@@ -1,5 +1,5 @@
 diff --git a/browser/base/content/aboutDialog.xhtml b/browser/base/content/aboutDialog.xhtml
-index e0fcce367abe57e03e54779437facbba4326687b..70ef3cf15e9384f05e76d0768efb07872d4b69cf 100644
+index 55de24241514d11f6a174dd97ca37c8a4a99b8af..1459c91ff11429788e103d385f1598b6275592c8 100644
 --- a/browser/base/content/aboutDialog.xhtml
 +++ b/browser/base/content/aboutDialog.xhtml
 @@ -36,6 +36,7 @@
@@ -20,7 +20,7 @@ index e0fcce367abe57e03e54779437facbba4326687b..70ef3cf15e9384f05e76d0768efb0787
            </description>
 +#if 0
            <description class="text-blurb" id="contributeDesc" data-l10n-id="helpus">
-             <label is="text-link" href="https://donate.mozilla.org/?utm_source=firefox&#38;utm_medium=referral&#38;utm_campaign=firefox_about&#38;utm_content=firefox_about" data-l10n-name="helpus-donateLink"/>
+             <label is="text-link" href="https://foundation.mozilla.org/?form=firefox-about" data-l10n-name="helpus-donateLink"/>
              <label is="text-link" href="https://www.mozilla.org/contribute/?utm_source=firefox-browser&#38;utm_medium=firefox-desktop&#38;utm_campaign=about-dialog" data-l10n-name="helpus-getInvolvedLink"/>
            </description>
 +#endif
diff --git a/src/browser/base/content/browser-box-inc-xhtml.patch b/src/browser/base/content/browser-box-inc-xhtml.patch
index f1bf19a97..434945cc1 100644
--- a/src/browser/base/content/browser-box-inc-xhtml.patch
+++ b/src/browser/base/content/browser-box-inc-xhtml.patch
@@ -1,12 +1,13 @@
 diff --git a/browser/base/content/browser-box.inc.xhtml b/browser/base/content/browser-box.inc.xhtml
-index d445abe7e743b2ec5d46d42f8f149c000e3c7997..b40fee5724a60171a8fa8849e6c778d2a17980f7 100644
+index 41258d81bbd2549a2d80cb7df9a9d65aa73a46f1..75bb0897710a478257d38c55c7fb0efb5aedd777 100644
 --- a/browser/base/content/browser-box.inc.xhtml
 +++ b/browser/base/content/browser-box.inc.xhtml
-@@ -2,27 +2,19 @@
+@@ -2,28 +2,17 @@
  # License, v. 2.0. If a copy of the MPL was not distributed with this
  # file, You can obtain one at http://mozilla.org/MPL/2.0/.
  
 -<hbox flex="1" id="browser">
+-  <html:sidebar-launcher id="sidebar-launcher" flex="1" hidden="true"></html:sidebar-launcher>
 -  <vbox id="sidebar-box" hidden="true" class="chromeclass-extrachrome">
 -    <box id="sidebar-header" align="center">
 -      <toolbarbutton id="sidebar-switcher-target" class="tabbable" aria-expanded="false">
@@ -23,9 +24,7 @@ index d445abe7e743b2ec5d46d42f8f149c000e3c7997..b40fee5724a60171a8fa8849e6c778d2
 -  <splitter id="sidebar-splitter" class="chromeclass-extrachrome sidebar-splitter" resizebefore="sibling" resizeafter="none" hidden="true"/>
 +<vbox id="browser">
    <vbox id="appcontent" flex="1">
-+
 +    <html:div id="zen-appcontent-navbar-container"></html:div>
-+
      <!-- gNotificationBox will be added here lazily. -->
 -    <tabbox id="tabbrowser-tabbox"
 +    <hbox id="zen-tabbox-wrapper" flex="1">
diff --git a/src/browser/base/content/browser-sidebar-js.patch b/src/browser/base/content/browser-sidebar-js.patch
deleted file mode 100644
index affc8a6b9..000000000
--- a/src/browser/base/content/browser-sidebar-js.patch
+++ /dev/null
@@ -1,12 +0,0 @@
-diff --git a/browser/base/content/browser-sidebar.js b/browser/base/content/browser-sidebar.js
-index ea6457a5c42f7bd2e002bd9234b8eb9bd23bbcc0..9a7b75481fc0968c295bae9ca46ac5da4aec96dc 100644
---- a/browser/base/content/browser-sidebar.js
-+++ b/browser/base/content/browser-sidebar.js
-@@ -305,6 +305,7 @@ var SidebarUI = {
-       this._box.setAttribute("positionend", true);
-     } else {
-       this._box.removeAttribute("positionend");
-+      this._box.style.order = 0;
-     }
- 
-     this.hideSwitcherPanel();
diff --git a/src/browser/base/content/zen-sidebar-box.inc.xhtml b/src/browser/base/content/zen-sidebar-box.inc.xhtml
index 402466231..550635bdc 100644
--- a/src/browser/base/content/zen-sidebar-box.inc.xhtml
+++ b/src/browser/base/content/zen-sidebar-box.inc.xhtml
@@ -1,3 +1,4 @@
+<html:sidebar-launcher id="sidebar-launcher" flex="1" hidden="true"></html:sidebar-launcher>
 <vbox id="sidebar-box" hidden="true" class="chromeclass-extrachrome">
   <box id="sidebar-header" align="center">
     <toolbarbutton id="sidebar-switcher-target" class="tabbable" aria-expanded="false">
diff --git a/src/browser/components/controlcenter/content/protectionsPanel-inc-xhtml.patch b/src/browser/components/controlcenter/content/protectionsPanel-inc-xhtml.patch
index 4cbed317f..8f74ba39e 100644
--- a/src/browser/components/controlcenter/content/protectionsPanel-inc-xhtml.patch
+++ b/src/browser/components/controlcenter/content/protectionsPanel-inc-xhtml.patch
@@ -19,12 +19,4 @@ index 29927139181e40fa9779038f996a08a2afc6f76b..ddb95da98de6aba014d69f040aabe6b3
              <image/>
            </toolbarbutton>
            <description id="protections-popup-toast-panel-tp-on-desc" data-l10n-id="protections-panel-etp-on-header"></description>
-@@ -36,7 +37,7 @@
-         </box>
-         <toolbarseparator></toolbarseparator>
- 
--        <html:div id="messaging-system-message-container" disabled="true">
-+        <html:div id="messaging-system-message-container">
-           <!-- Messaging System Messages will render in this container -->
-         </html:div>
-       </vbox>
+
diff --git a/src/browser/components/sidebar/browser-sidebar-js.patch b/src/browser/components/sidebar/browser-sidebar-js.patch
new file mode 100644
index 000000000..ab9ea014f
--- /dev/null
+++ b/src/browser/components/sidebar/browser-sidebar-js.patch
@@ -0,0 +1,12 @@
+diff --git a/browser/components/sidebar/browser-sidebar.js b/browser/components/sidebar/browser-sidebar.js
+index 55664f8cfc8ff7071e5d93fbf24b7471cfc4f879..398e78600e50bc1e2a8dbb2d64d6b578f4def28f 100644
+--- a/browser/components/sidebar/browser-sidebar.js
++++ b/browser/components/sidebar/browser-sidebar.js
+@@ -357,6 +357,7 @@ var SidebarUI = {
+     } else {
+       this._box.removeAttribute("positionend");
+       sidebarLauncher.removeAttribute("positionend");
++      this._box.style.order = 0;
+     }
+ 
+     this.hideSwitcherPanel();
diff --git a/src/browser/components/tabpreview/tab-preview-panel-mjs.patch b/src/browser/components/tabpreview/tab-preview-panel-mjs.patch
new file mode 100644
index 000000000..f93f05a4b
--- /dev/null
+++ b/src/browser/components/tabpreview/tab-preview-panel-mjs.patch
@@ -0,0 +1,13 @@
+diff --git a/browser/components/tabpreview/tab-preview-panel.mjs b/browser/components/tabpreview/tab-preview-panel.mjs
+index 683b2c17ec893a97680d885c622029591dda7f29..605f8682368d691f7cc18dfb1775fa2622006ebd 100644
+--- a/browser/components/tabpreview/tab-preview-panel.mjs
++++ b/browser/components/tabpreview/tab-preview-panel.mjs
+@@ -7,7 +7,7 @@ var { XPCOMUtils } = ChromeUtils.importESModule(
+ );
+ 
+ const POPUP_OPTIONS = {
+-  position: "bottomleft topleft",
++  position: "topright topleft",
+   x: 0,
+   y: -2,
+ };
diff --git a/src/browser/components/tabpreview/tabpreview-css.patch b/src/browser/components/tabpreview/tabpreview-css.patch
index e3340d6a3..d1168f22d 100644
--- a/src/browser/components/tabpreview/tabpreview-css.patch
+++ b/src/browser/components/tabpreview/tabpreview-css.patch
@@ -1,9 +1,9 @@
 diff --git a/browser/components/tabpreview/tabpreview.css b/browser/components/tabpreview/tabpreview.css
-index 776f520c7da2cf3e2dcc5f1395a3266f1c009ea0..2605963b023c507ab63c3ac8b761477da8550ce8 100644
+index e978266e5da72f3051d5455d7a3f2867a88648c5..c57e844107ea6e99b406422496e9b41511089594 100644
 --- a/browser/components/tabpreview/tabpreview.css
 +++ b/browser/components/tabpreview/tabpreview.css
-@@ -57,3 +57,24 @@
-     display: none;
+@@ -42,3 +42,24 @@
+     width: 100%;
    }
  }
 +
diff --git a/src/browser/components/tabpreview/tabpreview-mjs.patch b/src/browser/components/tabpreview/tabpreview-mjs.patch
deleted file mode 100644
index 8be88ad60..000000000
--- a/src/browser/components/tabpreview/tabpreview-mjs.patch
+++ /dev/null
@@ -1,22 +0,0 @@
-diff --git a/browser/components/tabpreview/tabpreview.mjs b/browser/components/tabpreview/tabpreview.mjs
-index 5256ab22ff3a79d9c020dac2ce375f5e42f9c13c..8dacc6b4e04b8b1848b1b6280e8132202d1b51b6 100644
---- a/browser/components/tabpreview/tabpreview.mjs
-+++ b/browser/components/tabpreview/tabpreview.mjs
-@@ -44,7 +44,7 @@ export default class TabPreview extends MozLitElement {
-       this,
-       "_prefDisplayThumbnail",
-       TAB_PREVIEW_USE_THUMBNAILS_PREF,
--      false
-+      true
-     );
-   }
- 
-@@ -109,7 +109,7 @@ export default class TabPreview extends MozLitElement {
- 
-   showPreview() {
-     this.panel.openPopup(this.tab, {
--      position: "bottomleft topleft",
-+      position: "topright topleft",
-       y: -2,
-       isContextMenu: false,
-     });
diff --git a/src/browser/themes/shared/browser-custom-colors-css.patch b/src/browser/themes/shared/browser-custom-colors-css.patch
index 09664483e..84d8b43a9 100644
--- a/src/browser/themes/shared/browser-custom-colors-css.patch
+++ b/src/browser/themes/shared/browser-custom-colors-css.patch
@@ -1,19 +1,19 @@
 diff --git a/browser/themes/shared/browser-custom-colors.css b/browser/themes/shared/browser-custom-colors.css
-index d98d56690f8e01fbf5cbb5050b2c71b726ed7323..5c14d3a57f6d9c17c43c934c7b8cb7f0a525d5d5 100644
+index 23187312740d440b3cd4b376a06cb2ab2e885604..3f16966196887609b7e734f194c346d9cc9fda4b 100644
 --- a/browser/themes/shared/browser-custom-colors.css
 +++ b/browser/themes/shared/browser-custom-colors.css
 @@ -6,7 +6,7 @@
  
  @media not (prefers-contrast) {
-   :root:not(:-moz-lwtheme) {
+   :root:not([lwtheme]) {
 -    --button-primary-bgcolor: light-dark(rgb(0, 97, 224), rgb(0, 221, 255));
 +    --button-primary-bgcolor: light-dark(#000, #fff);
      --button-primary-hover-bgcolor: light-dark(rgb(2, 80, 187), rgb(128, 235, 255));
      --button-primary-active-bgcolor: light-dark(rgb(5, 62, 148), rgb(170, 242, 255));
      --button-primary-color: light-dark(rgb(251, 251, 254), rgb(43, 42, 51));
-@@ -50,7 +50,7 @@
-     --tab-attention-icon-color: light-dark(rgb(42, 195, 162), rgb(84, 255, 189));
-     --tabs-navbar-shadow-color: transparent;
+@@ -49,7 +49,7 @@
+     --tab-icon-overlay-fill: light-dark(rgb(91, 91, 102), rgb(251, 251, 254));
+     --tabs-navbar-separator-style: none;
  
 -    --toolbox-non-lwt-bgcolor: light-dark(rgb(240, 240, 244), rgb(28, 27, 34));
 +    --toolbox-non-lwt-bgcolor: light-dark(rgb(210, 210, 213), rgb(28, 27, 34));
diff --git a/src/browser/themes/shared/browser-shared-css.patch b/src/browser/themes/shared/browser-shared-css.patch
index ba73addfc..1fef477b1 100644
--- a/src/browser/themes/shared/browser-shared-css.patch
+++ b/src/browser/themes/shared/browser-shared-css.patch
@@ -16,7 +16,7 @@ index 164b54bd857e5782e3885dcde5663f336de737de..d7cf63c4ac84f00641c4ac9bfa407beb
    appearance: none;
  
 -  /* Toolbar / content area border */
--  border-bottom: 1px solid var(--chrome-content-separator-color);
+-  border-bottom: 0.01px solid var(--chrome-content-separator-color);
 -
    background-color: var(--toolbox-non-lwt-bgcolor);
    color: var(--toolbox-non-lwt-textcolor);
@@ -33,7 +33,7 @@ index 164b54bd857e5782e3885dcde5663f336de737de..d7cf63c4ac84f00641c4ac9bfa407beb
 -    border-bottom-style: none;
 -  }
 -
--  &:-moz-lwtheme {
+-  :root[lwtheme] & {
 -    background-image: var(--lwt-additional-images);
 -    background-repeat: var(--lwt-background-tiling);
 -    background-position: var(--lwt-background-alignment);
diff --git a/src/toolkit/modules/LightweightThemeConsumer-sys-mjs.patch b/src/toolkit/modules/LightweightThemeConsumer-sys-mjs.patch
index 83ce14970..1521ff4f6 100644
--- a/src/toolkit/modules/LightweightThemeConsumer-sys-mjs.patch
+++ b/src/toolkit/modules/LightweightThemeConsumer-sys-mjs.patch
@@ -4,7 +4,7 @@ index 0d3993370b4ecbdfaf87cfd3145617343c29dc39..8587f7286476ca0dcce1bb02ef02ce0d
 +++ b/toolkit/modules/LightweightThemeConsumer.sys.mjs
 @@ -32,7 +32,7 @@ const toolkitVariableMap = [
        lwtProperty: "accentcolor",
-       processColor(rgbaChannels, element) {
+       processColor(rgbaChannels) {
          if (!rgbaChannels || rgbaChannels.a == 0) {
 -          return "white";
 +          return "var(--zen-colors-primary)";
@@ -14,7 +14,7 @@ index 0d3993370b4ecbdfaf87cfd3145617343c29dc39..8587f7286476ca0dcce1bb02ef02ce0d
 @@ -334,6 +334,7 @@ LightweightThemeConsumer.prototype = {
        theme.additionalBackgrounds
      );
-     _setProperties(root, active, theme, hasTheme);
+     _setProperties(root, hasTheme, theme);
 +    this._zenSetAccentColor(root);
  
      if (hasTheme) {
@@ -33,4 +33,4 @@ index 0d3993370b4ecbdfaf87cfd3145617343c29dc39..8587f7286476ca0dcce1bb02ef02ce0d
 +  },
  };
  
- function _getContentProperties(doc, active, data) {
+ function _getContentProperties(doc, hasTheme, data) {
diff --git a/src/toolkit/themes/shared/popup-css.patch b/src/toolkit/themes/shared/popup-css.patch
index 83efb1a2e..25d49e817 100644
--- a/src/toolkit/themes/shared/popup-css.patch
+++ b/src/toolkit/themes/shared/popup-css.patch
@@ -34,7 +34,7 @@ index 1426f9c4f6f24f19277006ead43eb88a50a408e5..8f8da0189772e00fb787d6708fce0481
    margin: calc(-1 * var(--panel-shadow-margin));
  
 @@ -30,8 +32,6 @@ panel {
-   --color-canvas: var(--panel-background);
+   --background-color-canvas: var(--panel-background);
  
    @media (-moz-platform: linux) {
 -    --panel-border-radius: 8px;