diff --git a/pkgs/by-name/cu/curlMinimal/fix-wakeup-consumption.patch b/pkgs/by-name/cu/curlMinimal/fix-wakeup-consumption.patch
deleted file mode 100644
index 0bc04b60bb87..000000000000
--- a/pkgs/by-name/cu/curlMinimal/fix-wakeup-consumption.patch
+++ /dev/null
@@ -1,32 +0,0 @@
-From 2a2104f3cff44bb28bb570a093be52bbeeed8f23 Mon Sep 17 00:00:00 2001
-From: Stefan Eissing <stefan@eissing.org>
-Date: Mon, 11 May 2026 14:56:04 +0200
-Subject: [PATCH] event: fix wakeup consumption
-
-The events on a multi wakeup socketpair were only consumed via
-curl_multi_poll()/curl_multi_wait() but not in event based processing on
-a curl_multi_socket() call. That led to busy loops as reported in
-
-Fixes #21547
-Reported-by: Earnestly on github
-Closes #21549
----
- lib/multi.c | 5 +++++
- 1 file changed, 5 insertions(+)
-
-diff --git a/lib/multi.c b/lib/multi.c
-index be32740a7097..5e84133f13fd 100644
---- a/lib/multi.c
-+++ b/lib/multi.c
-@@ -2703,6 +2703,11 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
-   Curl_uint32_bset_remove(&multi->dirty, data->mid);
- 
-   if(data == multi->admin) {
-+#ifdef ENABLE_WAKEUP
-+    /* Consume any pending wakeup signals before processing.
-+     * This is necessary for event based processing. See #21547 */
-+    (void)Curl_wakeup_consume(multi->wakeup_pair, TRUE);
-+#endif
- #ifdef USE_RESOLV_THREADED
-     Curl_async_thrdd_multi_process(multi);
- #endif
diff --git a/pkgs/by-name/cu/curlMinimal/package.nix b/pkgs/by-name/cu/curlMinimal/package.nix
index a25ea809c62b..832ffbbd04b6 100644
--- a/pkgs/by-name/cu/curlMinimal/package.nix
+++ b/pkgs/by-name/cu/curlMinimal/package.nix
@@ -84,7 +84,7 @@ assert
 
 stdenv.mkDerivation (finalAttrs: {
   pname = "curl";
-  version = "8.20.0";
+  version = "8.21.0";
 
   src = fetchurl {
     urls = [
@@ -93,16 +93,9 @@ stdenv.mkDerivation (finalAttrs: {
         builtins.replaceStrings [ "." ] [ "_" ] finalAttrs.version
       }/curl-${finalAttrs.version}.tar.xz"
     ];
-    hash = "sha256-Y/4twUi6DOromSLvg49+XJRicsLni3xZ+rS3nTziuJY=";
+    hash = "sha256-qhtmpw6s6D3GJFCHRWRsCK5WHeUSq0A63/uTrIf8cuY=";
   };
 
-  patches = [
-    # https://github.com/curl/curl/commit/2a2104f3cff44bb28bb570a093be52bbeeed8f23
-    # According to <https://curl.se/mail/distros-2026-05/0000.html>, this fixes
-    # a performance regression, causing high CPU usage
-    ./fix-wakeup-consumption.patch
-  ];
-
   # this could be accomplished by updateAutotoolsGnuConfigScriptsHook, but that causes infinite recursion
   # necessary for FreeBSD code path in configure
   postPatch = ''
diff --git a/pkgs/development/python-modules/pycapnp/default.nix b/pkgs/development/python-modules/pycapnp/default.nix
index c5c58935f5d4..d60a1b28d4b3 100644
--- a/pkgs/development/python-modules/pycapnp/default.nix
+++ b/pkgs/development/python-modules/pycapnp/default.nix
@@ -3,7 +3,6 @@
   buildPythonPackage,
   replaceVars,
   fetchFromGitHub,
-  fetchpatch,
   setuptools,
   wheel,
   capnproto,
@@ -36,12 +35,6 @@ buildPythonPackage rec {
     # other than the builtin schemas (based on quick GitHub code search), so I don't
     # think it's worthwhile.
     (replaceVars ./include-paths.patch { inherit capnproto; })
-
-    (fetchpatch {
-      url = "https://github.com/capnproto/pycapnp/commit/aa90ab6844df4718f02e2ca4974858d5ab0b079c.patch";
-      name = "python314-compat.patch";
-      hash = "sha256-pscOdgPotLZsW0XWyRTJigIDl3uWOizA1W0gQGZHSyg=";
-    })
   ];
 
   build-system = [
diff --git a/pkgs/development/python-modules/pycurl/default.nix b/pkgs/development/python-modules/pycurl/default.nix
index e37e001a3419..c7c32e9e20d3 100644
--- a/pkgs/development/python-modules/pycurl/default.nix
+++ b/pkgs/development/python-modules/pycurl/default.nix
@@ -4,6 +4,7 @@
   buildPythonPackage,
   isPyPy,
   fetchFromGitHub,
+  fetchpatch2,
   curl,
   openssl,
   bottle,
@@ -11,6 +12,7 @@
   flaky,
   flask,
   numpy,
+  websockets,
   setuptools,
 }:
 
@@ -28,6 +30,14 @@ buildPythonPackage rec {
     hash = "sha256-F40bJ7TYFK2dVkDJGGxl7XV46fKmjwvUYYulcwGL6hk=";
   };
 
+  patches = [
+    (fetchpatch2 {
+      name = "pycurl-curl-8.21.0-ws-support.patch";
+      url = "https://github.com/pycurl/pycurl/commit/c78fd8aba82e2f8037275063138eaa7706c111af.diff?full_index=1";
+      hash = "sha256-EBXgGiaMtXTsgJOOrzzZFJ7Q/ofAlc4zuipoEpfdFqU=";
+    })
+  ];
+
   preConfigure = ''
     substituteInPlace setup.py \
       --replace-fail '--static-libs' '--libs'
@@ -50,6 +60,7 @@ buildPythonPackage rec {
     flaky
     flask
     numpy
+    websockets
     pytestCheckHook
   ];
 
diff --git a/pkgs/tools/package-management/lix/common-lix.nix b/pkgs/tools/package-management/lix/common-lix.nix
index d5277055efd2..fdd550e8c8d1 100644
--- a/pkgs/tools/package-management/lix/common-lix.nix
+++ b/pkgs/tools/package-management/lix/common-lix.nix
@@ -39,6 +39,7 @@ assert lib.assertMsg (
   darwin,
   doxygen,
   editline,
+  fetchpatch2,
   flex,
   git,
   gtest,
@@ -127,16 +128,24 @@ let
         substitute $inputPath $out --replace-fail @deps@ "$(cat ${deps})"
       '';
 
-  # https://github.com/NixOS/nixpkgs/pull/525953 backported a performance patch
-  # that /somehow/ breaks Lix unit tests.
-  # FIXME revert when the patch is gone in curl drv
+  # curl 8.21.0 /somehow/ breaks Lix unit tests.
+  # See https://github.com/NixOS/nixpkgs/issues/534713
+  # FIXME remove once fixed
   curl-fixed = curl.overrideAttrs (
     {
       patches ? [ ],
       ...
     }:
     {
-      patches = lib.filter (patch: !lib.strings.hasSuffix "fix-wakeup-consumption.patch" patch) patches;
+      patches = patches ++ [
+        # See https://github.com/curl/curl/commit/2a2104f3cff44bb28bb570a093be52bbeeed8f23
+        (fetchpatch2 {
+          name = "fix-wakeup-consumption-revert.patch";
+          url = "https://github.com/curl/curl/commit/2a2104f3cff44bb28bb570a093be52bbeeed8f23.patch";
+          hash = "sha256-dkwr1ZaR7XB408JxeIKhuHxJrlwf3J01jL6lnOLXo1I=";
+          revert = true;
+        })
+      ];
     }
   );
 in