diff --git a/pkgs/os-specific/linux/kernel/kernels-org.json b/pkgs/os-specific/linux/kernel/kernels-org.json
index bd57aee756b0..e448d42e3e5f 100644
--- a/pkgs/os-specific/linux/kernel/kernels-org.json
+++ b/pkgs/os-specific/linux/kernel/kernels-org.json
@@ -1,30 +1,30 @@
 {
     "testing": {
-        "version": "6.12-rc5",
-        "hash": "sha256:18zh3nwhsz1hpyhmlim9a2hz8yvx5psrrav4346k46x9ybfardqy"
+        "version": "6.12-rc6",
+        "hash": "sha256:1cllyav4pg2z22a52j8vq1sdk8qrr6h8w2f3blrs4ispbhxa8xsb"
     },
     "6.1": {
-        "version": "6.1.115",
-        "hash": "sha256:0vxs6zj4p0ihcp11h3svqy3wa1yph0f1vzc8dlvqh60zgs1bmn0g"
+        "version": "6.1.116",
+        "hash": "sha256:109vhc1hcfx6sacw4553xmwbj1gqx3zqjq5zg11z7a72dqrnisqp"
     },
     "5.15": {
-        "version": "5.15.170",
-        "hash": "sha256:1ag7fvixhdcyxv6rqfsvq2wh02g64r4rx8izvfb33nfnld2nangx"
+        "version": "5.15.171",
+        "hash": "sha256:0fra5zwcixgl6fg9hgdzlfcqng6pg09h2j7xqhi4qg0jv1jf0lr9"
     },
     "5.10": {
-        "version": "5.10.228",
-        "hash": "sha256:0wkvn49sdy9ykyz6cqdqd9yplqfhc6b255w6wc17ky182mzqvk3n"
+        "version": "5.10.229",
+        "hash": "sha256:1q6di05rk4bsy91r03zw6vz14zzcpvv25dv7gw0yz1gzpgkbb9h8"
     },
     "5.4": {
-        "version": "5.4.284",
-        "hash": "sha256:0axkwfhvq3w2072xjqww476qa3rjglxyqmf72mlp9b5ymswil8kp"
+        "version": "5.4.285",
+        "hash": "sha256:1722sc365ajxmqyr4r49yp73mzdckay3rx5c2gx29xzny9zc6cmy"
     },
     "6.6": {
-        "version": "6.6.59",
-        "hash": "sha256:0vd76ccd4li4wsg04gc4nai9f4y1nknz967qby0i53y0v046hq93"
+        "version": "6.6.60",
+        "hash": "sha256:1vsjb7ifmf6ic6zv16fbrxjvffqc1mkndza76hjr9aw2a0ny7yaj"
     },
     "6.11": {
-        "version": "6.11.6",
-        "hash": "sha256:1kiky6viwrgm47slpv234lfq1wrwj29p5rx168gix3q0jw0zcm69"
+        "version": "6.11.7",
+        "hash": "sha256:1cpbycx79nl517rz573mja52bgzm249mhqzp424r5mqp91jfrx8b"
     }
 }
diff --git a/pkgs/os-specific/linux/kernel/linux-libre.nix b/pkgs/os-specific/linux/kernel/linux-libre.nix
index 4cdb819a6224..06adab0e0ac9 100644
--- a/pkgs/os-specific/linux/kernel/linux-libre.nix
+++ b/pkgs/os-specific/linux/kernel/linux-libre.nix
@@ -1,8 +1,8 @@
 { stdenv, lib, fetchsvn, linux
 , scripts ? fetchsvn {
     url = "https://www.fsfla.org/svn/fsfla/software/linux-libre/releases/branches/";
-    rev = "19643";
-    sha256 = "1gnji0hglzh6kj9ssawlrix1vlbcyfjdjx5d9qwpnn2p0sgsq7nj";
+    rev = "19663";
+    sha256 = "126b05v6hcdag3pfaxwbabfwkrp4c7010v52rk2dqh9i631ykavd";
   }
 , ...
 } @ args:
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 a1cd2eb5d93f..bd48959b2b23 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 = "5.15.167-rt79"; # updated by ./update-rt.sh
+  version = "5.15.170-rt81"; # updated by ./update-rt.sh
   branch = lib.versions.majorMinor version;
   kversion = builtins.elemAt (lib.splitString "-" version) 0;
 in buildLinux (args // {
@@ -19,14 +19,14 @@ in buildLinux (args // {
 
   src = fetchurl {
     url = "mirror://kernel/linux/kernel/v5.x/linux-${kversion}.tar.xz";
-    sha256 = "0c6s6l5sz9ibws7bymb393ww0z9i3amsk1yx0bahipz3xhc1yxdi";
+    sha256 = "1ag7fvixhdcyxv6rqfsvq2wh02g64r4rx8izvfb33nfnld2nangx";
   };
 
   kernelPatches = let rt-patch = {
     name = "rt";
     patch = fetchurl {
       url = "mirror://kernel/linux/kernel/projects/rt/${branch}/older/patch-${version}.patch.xz";
-      sha256 = "0z9yhg0vxzrqn2vyg973pd8qy5iq30jkza8c0mrjjpjzyc8jvm57";
+      sha256 = "0vr6c93dr0gcszx0hfnfhqbg5flkvxmkpf2hw13gi4rg8x4bx5ll";
     };
   }; in [ rt-patch ] ++ kernelPatches;
 
diff --git a/pkgs/os-specific/linux/kernel/linux-rt-6.1.nix b/pkgs/os-specific/linux/kernel/linux-rt-6.1.nix
index 29a40809d0fc..16c4f021ed00 100644
--- a/pkgs/os-specific/linux/kernel/linux-rt-6.1.nix
+++ b/pkgs/os-specific/linux/kernel/linux-rt-6.1.nix
@@ -6,7 +6,7 @@
 , ... } @ args:
 
 let
-  version = "6.1.111-rt42"; # updated by ./update-rt.sh
+  version = "6.1.112-rt43"; # updated by ./update-rt.sh
   branch = lib.versions.majorMinor version;
   kversion = builtins.elemAt (lib.splitString "-" version) 0;
 in buildLinux (args // {
@@ -19,14 +19,14 @@ in buildLinux (args // {
 
   src = fetchurl {
     url = "mirror://kernel/linux/kernel/v6.x/linux-${kversion}.tar.xz";
-    sha256 = "1c7d49kppv8xgqlsrfm1286mnvz8vcnbqqh6zgfca2s13px9hwn4";
+    sha256 = "094z3wfcxqx2rbi072i5frshpy6rdvk39aahwm9nc07vc8sxxn4b";
   };
 
   kernelPatches = let rt-patch = {
     name = "rt";
     patch = fetchurl {
       url = "mirror://kernel/linux/kernel/projects/rt/${branch}/older/patch-${version}.patch.xz";
-      sha256 = "16yb962fkkvgppbx8glp5ph3h1jl2q1b4m2s8gsf3k9i9yim7v5c";
+      sha256 = "0qvil92xkbwmyrmj0zlg0ssg95ncscmr4ga4380903bqhhh74d6h";
     };
   }; in [ rt-patch ] ++ kernelPatches;
 
diff --git a/pkgs/os-specific/linux/kernel/linux-rt-6.6.nix b/pkgs/os-specific/linux/kernel/linux-rt-6.6.nix
index c27ae8cf120a..ffbe4fc47e4c 100644
--- a/pkgs/os-specific/linux/kernel/linux-rt-6.6.nix
+++ b/pkgs/os-specific/linux/kernel/linux-rt-6.6.nix
@@ -6,7 +6,7 @@
 , ... } @ args:
 
 let
-  version = "6.6.52-rt43"; # updated by ./update-rt.sh
+  version = "6.6.58-rt45"; # updated by ./update-rt.sh
   branch = lib.versions.majorMinor version;
   kversion = builtins.elemAt (lib.splitString "-" version) 0;
 in buildLinux (args // {
@@ -19,14 +19,14 @@ in buildLinux (args // {
 
   src = fetchurl {
     url = "mirror://kernel/linux/kernel/v6.x/linux-${kversion}.tar.xz";
-    sha256 = "1f5l6y7abscm01dr740fzvq8r756ar854n0i299smm4rhcsap48m";
+    sha256 = "1nwrd017l5m4w12yrcf31y3g0l9xqm5b0fzcqdgan3ypi3jq3pz7";
   };
 
   kernelPatches = let rt-patch = {
     name = "rt";
     patch = fetchurl {
       url = "mirror://kernel/linux/kernel/projects/rt/${branch}/older/patch-${version}.patch.xz";
-      sha256 = "0g33n9idc3lhbj5z637zm3bgqh601a05cl1s8ji8zbnfh971jcgh";
+      sha256 = "0npvydlk2z33c5xqhg31xky045s5rvjnvfqml30nycmzbsmqjc7c";
     };
   }; in [ rt-patch ] ++ kernelPatches;
 
diff --git a/pkgs/os-specific/linux/kernel/update-mainline.py b/pkgs/os-specific/linux/kernel/update-mainline.py
index 320d5065fefa..13e89d3df1e1 100755
--- a/pkgs/os-specific/linux/kernel/update-mainline.py
+++ b/pkgs/os-specific/linux/kernel/update-mainline.py
@@ -87,9 +87,8 @@ def get_hash(kernel: KernelRelease):
     return f"sha256:{hash}"
 
 
-def get_oldest_branch() -> Version:
-    with open(VERSIONS_FILE) as f:
-        return parse_version(sorted(json.load(f).keys())[0])
+def get_oldest_branch(kernels) -> Version:
+    return min(parse_version(v) for v in kernels.keys() if v != "testing")
 
 
 def predates_oldest_branch(oldest: Version, to_compare: str) -> bool:
@@ -118,8 +117,7 @@ def main():
         if (parsed := parse_release(release)) is not None
     ]
     all_kernels = json.load(VERSIONS_FILE.open())
-
-    oldest_branch = get_oldest_branch()
+    oldest_branch = get_oldest_branch(all_kernels)
 
     for (branch, kernels) in groupby(parsed_releases, lambda kernel: kernel.branch):
         kernel = max(kernels, key=lambda kernel: kernel.parsed_version)