diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index 7e56f724016d..1b4a6236c94e 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -56,12 +56,12 @@
 
   firefox-devedition = buildMozillaMach rec {
     pname = "firefox-devedition";
-    version = "115.0b7";
+    version = "115.0b9";
     applicationName = "Mozilla Firefox Developer Edition";
     branding = "browser/branding/aurora";
     src = fetchurl {
       url = "mirror://mozilla/devedition/releases/${version}/source/firefox-${version}.source.tar.xz";
-      sha512 = "f360ca7c5eb69d16a54b37a95195f4981c19e7e081cf7d494dafc1838ec69f2beabae5eaed23b0b551e71b32e3d0213383bc43e63416d390aa453bfa8b0f1993";
+      sha512 = "8d2a0dc2c64f8fc846077165ea0c97cae04a85db9ffcd23fbf933b25f165ecd85727ba2f432842f2d2f41c5b5bef5eb4ae2536d8492888c334aba0dcec278c47";
     };
 
     meta = {