diff --git a/doc/release-notes/rl-2605.section.md b/doc/release-notes/rl-2605.section.md
index ed1f18a3c3bb..b1023b71f107 100644
--- a/doc/release-notes/rl-2605.section.md
+++ b/doc/release-notes/rl-2605.section.md
@@ -228,6 +228,8 @@
 
 - All Xfce packages have been moved to top level (e.g. if you previously added `pkgs.xfce.xfce4-whiskermenu-plugin` to `environment.systemPackages`, you will need to change it to `pkgs.xfce4-whiskermenu-plugin`). The `xfce` scope will be removed in NixOS 26.11.
 
+- The Dovecot IMAP server has been updated to version 2.4, with the `dovecot` attribute now referring to this backwards-incompatible version. The attribute `dovecot_2_3` refers to the previous version. The Pigeonhole plugin has been similarly updated to 2.4, with the version compatible with Dovecot 2.3 being at `dovecot_pigeonhole_0_5`. See <https://doc.dovecot.org/latest/installation/upgrade/2.3-to-2.4.html> for more information on how to upgrade.
+
 - `spacefm` was removed because it appeared to be unmaintained upstream.
 
 - `vimPlugins.nvim-treesitter` has been updated to `main` branch, which is a full and incompatible rewrite. If you can't or don't want to update, you should use `vimPlugins.nvim-treesitter-legacy`.
diff --git a/pkgs/by-name/do/dovecot/2.3.nix b/pkgs/by-name/do/dovecot/2.3.nix
new file mode 100644
index 000000000000..3b8ad371034e
--- /dev/null
+++ b/pkgs/by-name/do/dovecot/2.3.nix
@@ -0,0 +1,18 @@
+import ./generic.nix {
+  version = "2.3.21.1";
+  hash = "sha256-1THBB401r6AnZbnHGhIq+o+nR8v94O0mIX68Pv0miiE=";
+  patches = fetchpatch: [
+    # Fix loading extended modules.
+    ./load-extended-modules.patch
+    # fix openssl 3.0 compatibility
+    (fetchpatch {
+      url = "https://salsa.debian.org/debian/dovecot/-/raw/debian/1%252.3.19.1+dfsg1-2/debian/patches/Support-openssl-3.0.patch";
+      hash = "sha256-PbBB1jIY3jIC8Js1NY93zkV0gISGUq7Nc67Ul5tN7sw=";
+    })
+    (fetchpatch {
+      name = "dovecot-test-data-stack-drop-bogus-assertion.patch";
+      url = "https://github.com/dovecot/core/commit/9f642dd868db6e7401f24e4fb4031b5bdca8aae7.patch";
+      hash = "sha256-dAX80dRqOba9Fkzl11ChYJ6vqcgfkaw/o+TOQKCnnns=";
+    })
+  ];
+}
diff --git a/pkgs/by-name/do/dovecot/2.4.nix b/pkgs/by-name/do/dovecot/2.4.nix
deleted file mode 100644
index 7421368e2a3e..000000000000
--- a/pkgs/by-name/do/dovecot/2.4.nix
+++ /dev/null
@@ -1,8 +0,0 @@
-import ./generic.nix {
-  version = "2.4.3";
-  hash = "sha256-NTtQMHK/IzAYHKb1lxClUUJkyJpeLo7mKRCAR1GaUTo=";
-  patches = _: [
-    # Fix loading extended modules.
-    ./load-extended-modules.patch
-  ];
-}
diff --git a/pkgs/by-name/do/dovecot/generic.nix b/pkgs/by-name/do/dovecot/generic.nix
index 49d809e6fae5..fbdfcef9557a 100644
--- a/pkgs/by-name/do/dovecot/generic.nix
+++ b/pkgs/by-name/do/dovecot/generic.nix
@@ -33,8 +33,7 @@
   fetchpatch,
   rpcsvc-proto,
   libtirpc,
-  dovecot_pigeonhole_0_5,
-  dovecot_pigeonhole ? dovecot_pigeonhole_0_5,
+  dovecot_pigeonhole,
   withApparmor ? false,
   libapparmor,
   withLDAP ? true,
diff --git a/pkgs/by-name/do/dovecot/package.nix b/pkgs/by-name/do/dovecot/package.nix
index 3b8ad371034e..7421368e2a3e 100644
--- a/pkgs/by-name/do/dovecot/package.nix
+++ b/pkgs/by-name/do/dovecot/package.nix
@@ -1,18 +1,8 @@
 import ./generic.nix {
-  version = "2.3.21.1";
-  hash = "sha256-1THBB401r6AnZbnHGhIq+o+nR8v94O0mIX68Pv0miiE=";
-  patches = fetchpatch: [
+  version = "2.4.3";
+  hash = "sha256-NTtQMHK/IzAYHKb1lxClUUJkyJpeLo7mKRCAR1GaUTo=";
+  patches = _: [
     # Fix loading extended modules.
     ./load-extended-modules.patch
-    # fix openssl 3.0 compatibility
-    (fetchpatch {
-      url = "https://salsa.debian.org/debian/dovecot/-/raw/debian/1%252.3.19.1+dfsg1-2/debian/patches/Support-openssl-3.0.patch";
-      hash = "sha256-PbBB1jIY3jIC8Js1NY93zkV0gISGUq7Nc67Ul5tN7sw=";
-    })
-    (fetchpatch {
-      name = "dovecot-test-data-stack-drop-bogus-assertion.patch";
-      url = "https://github.com/dovecot/core/commit/9f642dd868db6e7401f24e4fb4031b5bdca8aae7.patch";
-      hash = "sha256-dAX80dRqOba9Fkzl11ChYJ6vqcgfkaw/o+TOQKCnnns=";
-    })
   ];
 }
diff --git a/pkgs/by-name/do/dovecot_pigeonhole/0.5.nix b/pkgs/by-name/do/dovecot_pigeonhole/0.5.nix
new file mode 100644
index 000000000000..4de2e7419269
--- /dev/null
+++ b/pkgs/by-name/do/dovecot_pigeonhole/0.5.nix
@@ -0,0 +1,10 @@
+import ./generic.nix {
+  version = "0.5.21.1";
+  url =
+    {
+      version,
+      dovecotMajorMinor,
+    }:
+    "https://pigeonhole.dovecot.org/releases/${dovecotMajorMinor}/dovecot-${dovecotMajorMinor}-pigeonhole-${version}.tar.gz";
+  hash = "sha256-andOWZmgWYIPATEk0V+mHmReL+quG81azwPkBMoo9OE=";
+}
diff --git a/pkgs/by-name/do/dovecot_pigeonhole/2.4.nix b/pkgs/by-name/do/dovecot_pigeonhole/2.4.nix
deleted file mode 100644
index ca18eaa2d271..000000000000
--- a/pkgs/by-name/do/dovecot_pigeonhole/2.4.nix
+++ /dev/null
@@ -1,17 +0,0 @@
-import ./generic.nix {
-  version = "2.4.3";
-  url =
-    {
-      version,
-      dovecotMajorMinor,
-    }:
-    "https://pigeonhole.dovecot.org/releases/${dovecotMajorMinor}/dovecot-pigeonhole-${version}.tar.gz";
-  hash = "sha256-LQNhqYnBVICabluj8F07UOZR5frt6bd9JSyuHJDS6hc=";
-  patches = fetchpatch: [
-    # https://github.com/NixOS/nixpkgs/pull/388463#issuecomment-3066016707
-    (fetchpatch {
-      url = "https://github.com/dovecot/pigeonhole/commit/517d74aa1d98b853b72608ce722bc58009c0f4a9.patch";
-      hash = "sha256-BLBz9ZhOGEIIitnXG0uM6bZBRNnQBy4K2IJlh1+Un50=";
-    })
-  ];
-}
diff --git a/pkgs/by-name/do/dovecot_pigeonhole/generic.nix b/pkgs/by-name/do/dovecot_pigeonhole/generic.nix
index 5f11b695efa1..fca1f17172ec 100644
--- a/pkgs/by-name/do/dovecot_pigeonhole/generic.nix
+++ b/pkgs/by-name/do/dovecot_pigeonhole/generic.nix
@@ -9,8 +9,7 @@
   stdenv,
   fetchpatch,
   fetchzip,
-  dovecot_2_3,
-  dovecot ? dovecot_2_3,
+  dovecot,
   openssl,
   libstemmer,
   perl,
diff --git a/pkgs/by-name/do/dovecot_pigeonhole/package.nix b/pkgs/by-name/do/dovecot_pigeonhole/package.nix
index 4de2e7419269..ca18eaa2d271 100644
--- a/pkgs/by-name/do/dovecot_pigeonhole/package.nix
+++ b/pkgs/by-name/do/dovecot_pigeonhole/package.nix
@@ -1,10 +1,17 @@
 import ./generic.nix {
-  version = "0.5.21.1";
+  version = "2.4.3";
   url =
     {
       version,
       dovecotMajorMinor,
     }:
-    "https://pigeonhole.dovecot.org/releases/${dovecotMajorMinor}/dovecot-${dovecotMajorMinor}-pigeonhole-${version}.tar.gz";
-  hash = "sha256-andOWZmgWYIPATEk0V+mHmReL+quG81azwPkBMoo9OE=";
+    "https://pigeonhole.dovecot.org/releases/${dovecotMajorMinor}/dovecot-pigeonhole-${version}.tar.gz";
+  hash = "sha256-LQNhqYnBVICabluj8F07UOZR5frt6bd9JSyuHJDS6hc=";
+  patches = fetchpatch: [
+    # https://github.com/NixOS/nixpkgs/pull/388463#issuecomment-3066016707
+    (fetchpatch {
+      url = "https://github.com/dovecot/pigeonhole/commit/517d74aa1d98b853b72608ce722bc58009c0f4a9.patch";
+      hash = "sha256-BLBz9ZhOGEIIitnXG0uM6bZBRNnQBy4K2IJlh1+Un50=";
+    })
+  ];
 }
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 305ece210f28..3ffabf922308 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -8070,15 +8070,15 @@ with pkgs;
 
   dodgy = with python3Packages; toPythonApplication dodgy;
 
-  dovecot_2_3 = dovecot;
-  dovecot_2_4 = callPackage ../by-name/do/dovecot/2.4.nix {
-    dovecot_pigeonhole = dovecot_pigeonhole_2_4;
+  dovecot_2_3 = callPackage ../by-name/do/dovecot/2.3.nix {
+    dovecot_pigeonhole = dovecot_pigeonhole_0_5;
   };
+  dovecot_2_4 = dovecot;
 
-  dovecot_pigeonhole_0_5 = dovecot_pigeonhole;
-  dovecot_pigeonhole_2_4 = callPackage ../by-name/do/dovecot_pigeonhole/2.4.nix {
-    dovecot = dovecot_2_4;
+  dovecot_pigeonhole_0_5 = callPackage ../by-name/do/dovecot_pigeonhole/0.5.nix {
+    dovecot = dovecot_2_3;
   };
+  dovecot_pigeonhole_2_4 = dovecot_pigeonhole;
 
   inherit (callPackages ../servers/firebird { })
     firebird_4