diff --git a/nixos/tests/haproxy.nix b/nixos/tests/haproxy.nix
index 2c3878131b6..b6ff4102fe6 100644
--- a/nixos/tests/haproxy.nix
+++ b/nixos/tests/haproxy.nix
@@ -16,7 +16,6 @@ import ./make-test-python.nix ({ pkgs, ...}: {
           frontend http
             bind *:80
             mode http
-            option http-use-htx
             http-request use-service prometheus-exporter if { path /metrics }
             use_backend http_server
         '';
diff --git a/pkgs/tools/networking/haproxy/default.nix b/pkgs/tools/networking/haproxy/default.nix
index 529339e3465..87cb304ed50 100644
--- a/pkgs/tools/networking/haproxy/default.nix
+++ b/pkgs/tools/networking/haproxy/default.nix
@@ -11,11 +11,11 @@ assert usePcre -> pcre != null;
 
 stdenv.mkDerivation rec {
   pname = "haproxy";
-  version = "2.3.14";
+  version = "2.5.1";
 
   src = fetchurl {
     url = "https://www.haproxy.org/download/${lib.versions.majorMinor version}/src/${pname}-${version}.tar.gz";
-    sha256 = "0ah6xsxlk1a7jsxdg0pbdhzhssz9ysrfxd3bs5hm1shql1jmqzh4";
+    sha256 = "sha256-PpB5DfyDKvpspP30Uo3izi508+H3S+0NcK1UvVkg6VQ=";
   };
 
   buildInputs = [ openssl zlib ]
@@ -47,7 +47,7 @@ stdenv.mkDerivation rec {
     "USE_SYSTEMD=yes"
     "USE_GETADDRINFO=1"
   ] ++ lib.optionals withPrometheusExporter [
-    "EXTRA_OBJS=contrib/prometheus-exporter/service-prometheus.o"
+    "USE_PROMEX=yes"
   ] ++ [ "CC=${stdenv.cc.targetPrefix}cc" ];
 
   enableParallelBuilding = true;