diff --git a/pkgs/development/python-modules/html5lib/default.nix b/pkgs/development/python-modules/html5lib/default.nix
index fb6e80b44995..990ccacb4fbc 100644
--- a/pkgs/development/python-modules/html5lib/default.nix
+++ b/pkgs/development/python-modules/html5lib/default.nix
@@ -1,47 +1,48 @@
 {
   lib,
   buildPythonPackage,
-  fetchPypi,
-  fetchpatch,
+  fetchFromGitHub,
+  setuptools,
   six,
   webencodings,
-  mock,
   pytest-expect,
   pytestCheckHook,
+  unstableGitUpdater,
 }:
 
-buildPythonPackage rec {
+buildPythonPackage {
   pname = "html5lib";
-  version = "1.1";
-  format = "setuptools";
+  version = "1.1-unstable-2024-02-21";
+  pyproject = true;
 
-  src = fetchPypi {
-    inherit pname version;
-    sha256 = "b2e5b40261e20f354d198eae92afc10d750afb487ed5e50f9c4eaf07c184146f";
+  src = fetchFromGitHub {
+    owner = "html5lib";
+    repo = "html5lib-python";
+    rev = "fd4f032bc090d44fb11a84b352dad7cbee0a4745";
+    hash = "sha256-Hyte1MEqlrD2enfunK1qtm3FJlUDqmhSyrCjo7VaBgA=";
   };
 
   patches = [
-    # Fix compatibility with pytest 6.
-    # Will be included in the next release after 1.1.
-    (fetchpatch {
-      url = "https://github.com/html5lib/html5lib-python/commit/2c19b9899ab3a3e8bd0ca35e5d78544334204169.patch";
-      hash = "sha256-VGCeB6o2QO/skeCZs8XLPfgEYVOSRL8cCpG7ajbZWEs=";
-    })
+    # https://github.com/html5lib/html5lib-python/pull/583
+    ./python314-compat.patch
   ];
 
-  propagatedBuildInputs = [
+  build-system = [ setuptools ];
+
+  dependencies = [
     six
     webencodings
   ];
 
-  # latest release not compatible with pytest 6
-  doCheck = false;
   nativeCheckInputs = [
-    mock
     pytest-expect
     pytestCheckHook
   ];
 
+  passthru.updateScript = unstableGitUpdater {
+    branch = "master";
+  };
+
   meta = {
     homepage = "https://github.com/html5lib/html5lib-python";
     downloadPage = "https://github.com/html5lib/html5lib-python/releases";
diff --git a/pkgs/development/python-modules/html5lib/python314-compat.patch b/pkgs/development/python-modules/html5lib/python314-compat.patch
new file mode 100644
index 000000000000..5351032f1232
--- /dev/null
+++ b/pkgs/development/python-modules/html5lib/python314-compat.patch
@@ -0,0 +1,26 @@
+From 379f9476c2a5ee370cd7ec856ee9092cace88499 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Miro=20Hron=C4=8Dok?= <miro@hroncok.cz>
+Date: Wed, 30 Oct 2024 15:44:40 +0100
+Subject: [PATCH] Avoid ast.Str on Python 3.8+
+
+It has been deprecated since Python 3.8 and was removed from Python 3.14+.
+---
+ setup.py | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/setup.py b/setup.py
+index 30ee0575..62272c18 100644
+--- a/setup.py
++++ b/setup.py
+@@ -93,8 +93,9 @@ def default_environment():
+         if (len(a.targets) == 1 and
+                 isinstance(a.targets[0], ast.Name) and
+                 a.targets[0].id == "__version__" and
+-                isinstance(a.value, ast.Str)):
+-            version = a.value.s
++                ((sys.version_info >= (3, 8) and isinstance(a.value, ast.Constant)) or
++                    isinstance(a.value, ast.Str))):
++            version = a.value.value if sys.version_info >= (3, 8) else a.value.s
+ 
+ setup(name='html5lib',
+       version=version,