diff --git a/pkgs/os-specific/linux/kernel/linux-rt-5.15.nix b/pkgs/os-specific/linux/kernel/linux-rt-5.15.nix
index 2b2f3464ecee..15ddf9df9147 100644
--- a/pkgs/os-specific/linux/kernel/linux-rt-5.15.nix
+++ b/pkgs/os-specific/linux/kernel/linux-rt-5.15.nix
@@ -6,7 +6,7 @@
 , ... } @ args:
 
 let
-  version = "5.15.79-rt54"; # updated by ./update-rt.sh
+  version = "5.15.86-rt56"; # updated by ./update-rt.sh
   branch = lib.versions.majorMinor version;
   kversion = builtins.elemAt (lib.splitString "-" version) 0;
 in buildLinux (args // {
@@ -18,14 +18,14 @@ in buildLinux (args // {
 
   src = fetchurl {
     url = "mirror://kernel/linux/kernel/v5.x/linux-${kversion}.tar.xz";
-    sha256 = "0m61k7k6lj24z9a266q08wzghggjik2wizcabdwd1vn0vcqr18yb";
+    sha256 = "1vpjnmwqsx6akph2nvbsv2jl7pp8b7xns3vmwbljsl23lkpxkz40";
   };
 
   kernelPatches = let rt-patch = {
     name = "rt";
     patch = fetchurl {
       url = "mirror://kernel/linux/kernel/projects/rt/${branch}/older/patch-${version}.patch.xz";
-      sha256 = "098dml58d2nf7qhwn1pznqk7wvsh83rh85gsw7nmn2dym08510p9";
+      sha256 = "0y7pkzacxh1fsvnbmjq0ljfb4zjw6dq9br6rl8kr3w4dj56fmaxs";
     };
   }; in [ rt-patch ] ++ kernelPatches;