diff --git a/pkgs/applications/networking/browsers/firefox/common.nix b/pkgs/applications/networking/browsers/firefox/common.nix
index 5542ca62b93a8..183b49b909d8d 100644
--- a/pkgs/applications/networking/browsers/firefox/common.nix
+++ b/pkgs/applications/networking/browsers/firefox/common.nix
@@ -254,7 +254,8 @@ buildStdenv.mkDerivation {
   ]
   ++ lib.optional (lib.versionOlder version "111") ./env_var_for_system_dir-ff86.patch
   ++ lib.optional (lib.versionAtLeast version "111") ./env_var_for_system_dir-ff111.patch
-  ++ lib.optional (lib.versionAtLeast version "96") ./no-buildconfig-ffx96.patch
+  ++ lib.optional (lib.versionAtLeast version "96" && lib.versionOlder version "121") ./no-buildconfig-ffx96.patch
+  ++ lib.optional (lib.versionAtLeast version "121") ./no-buildconfig-ffx121.patch
   ++ extraPatches;
 
   postPatch = ''
diff --git a/pkgs/applications/networking/browsers/firefox/no-buildconfig-ffx121.patch b/pkgs/applications/networking/browsers/firefox/no-buildconfig-ffx121.patch
new file mode 100644
index 0000000000000..999d0bd8e7f34
--- /dev/null
+++ b/pkgs/applications/networking/browsers/firefox/no-buildconfig-ffx121.patch
@@ -0,0 +1,27 @@
+diff --git a/docshell/base/nsAboutRedirector.cpp b/docshell/base/nsAboutRedirector.cpp
+index cfbc39527b02..9327631a79c5 100644
+--- a/docshell/base/nsAboutRedirector.cpp
++++ b/docshell/base/nsAboutRedirector.cpp
+@@ -88,9 +88,6 @@ static const RedirEntry kRedirMap[] = {
+     {"about", "chrome://global/content/aboutAbout.html", 0},
+     {"addons", "chrome://mozapps/content/extensions/aboutaddons.html",
+      nsIAboutModule::ALLOW_SCRIPT | nsIAboutModule::IS_SECURE_CHROME_UI},
+-    {"buildconfig", "chrome://global/content/buildconfig.html",
+-     nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
+-         nsIAboutModule::IS_SECURE_CHROME_UI},
+     {"checkerboard", "chrome://global/content/aboutCheckerboard.html",
+      nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
+          nsIAboutModule::ALLOW_SCRIPT},
+diff --git a/toolkit/content/jar.mn b/toolkit/content/jar.mn
+index ed7c2ad3fc30..ff54456a6582 100644
+--- a/toolkit/content/jar.mn
++++ b/toolkit/content/jar.mn
+@@ -41,8 +41,6 @@ toolkit.jar:
+    content/global/aboutUrlClassifier.js
+    content/global/aboutUrlClassifier.xhtml
+    content/global/aboutUrlClassifier.css
+-*   content/global/buildconfig.html
+-   content/global/buildconfig.css
+    content/global/contentAreaUtils.js
+    content/global/datepicker.xhtml
+ #ifndef MOZ_FENNEC
diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index 58a6586c4d5b1..2d08f391d283f 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -30,14 +30,15 @@
 
   firefox-beta = buildMozillaMach rec {
     pname = "firefox-beta";
-    version = "120.0b9";
+    version = "121.0b3";
     applicationName = "Mozilla Firefox Beta";
     src = fetchurl {
       url = "mirror://mozilla/firefox/releases/${version}/source/firefox-${version}.source.tar.xz";
-      sha512 = "7ac5562ce393ea84663eac5c6ee1a0ca527ff4a8a9ec6aaaef37213ff071076846949e80af21d95ec8e32d3cbc740b772a9d7cc54965b7bbc8e015da22ae927f";
+      sha512 = "95dd68c50af5784c44e40ad3a8ac6b4fb259fa8f56bc5e5de940d03dec1838b143712680826b4d260fefdad314464d24679911f21b1095512a86cdf4eb2648c9";
     };
 
     meta = {
+      changelog = "https://www.mozilla.org/en-US/firefox/${lib.versions.majorMinor version}beta/releasenotes/";
       description = "A web browser built from Firefox Beta Release source tree";
       homepage = "http://www.mozilla.com/en-US/firefox/";
       maintainers = with lib.maintainers; [ jopejoe1 ];
@@ -58,16 +59,17 @@
 
   firefox-devedition = buildMozillaMach rec {
     pname = "firefox-devedition";
-    version = "120.0b9";
+    version = "121.0b3";
     applicationName = "Mozilla Firefox Developer Edition";
     requireSigning = false;
     branding = "browser/branding/aurora";
     src = fetchurl {
       url = "mirror://mozilla/devedition/releases/${version}/source/firefox-${version}.source.tar.xz";
-      sha512 = "07bf1a58550e70c683719adef55fa3d1ee06876e0cb086c28242879c683269c4aa784b1dce639218b3ad24a546192088fe5224a52e13a0086f205ec5470e2428";
+      sha512 = "a5ed25159e63122f27bd05810eaf665834022ae407c029734ad41ef1ed5e3956497873f5210b7c385245056718837bd17c47cfc2e2e438a4c3274d2462ce51f8";
     };
 
     meta = {
+      changelog = "https://www.mozilla.org/en-US/firefox/${lib.versions.majorMinor version}beta/releasenotes/";
       description = "A web browser built from Firefox Developer Edition source tree";
       homepage = "http://www.mozilla.com/en-US/firefox/";
       maintainers = with lib.maintainers; [ jopejoe1 ];
diff --git a/pkgs/development/libraries/nss/latest.nix b/pkgs/development/libraries/nss/latest.nix
index c4d619e771441..9244978061eeb 100644
--- a/pkgs/development/libraries/nss/latest.nix
+++ b/pkgs/development/libraries/nss/latest.nix
@@ -5,6 +5,6 @@
 #       Example: nix-shell ./maintainers/scripts/update.nix --argstr package cacert
 
 import ./generic.nix {
-  version = "3.94";
-  hash = "sha256-RjrhgO6eXunjrU9ikyZlfiNngMyGVXKpMKFlIKutndg=";
+  version = "3.95";
+  hash = "sha256-RpiI5B6KeABRzgDtzZFOimvTjaiKgs+4SJjdOIY1gio=";
 }