diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index a0869a0..5aecadf 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -46,11 +46,10 @@ jobs:
             runs-on: "3.10"
           - name: CPython 3.11
             runs-on: "3.11"
-          # Following are disabled because of https://github.com/ethereum/eth-tester/issues/276
-          # - name: CPython 3.12
-          #   runs-on: "3.12"
-          # Waaaay to soon for 3.13
-          # - name: CPython 3.13-dev
+          - name: CPython 3.12
+            runs-on: "3.12"
+          # Not yet working, lets revisit later
+          # - name: CPython 3.13
           #   runs-on: "3.13-dev"
     steps:
       - uses: actions/checkout@v4
diff --git a/pyproject.toml b/pyproject.toml
index ab06667..2f233ea 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,6 +29,7 @@ classifiers = [
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
+  # "Programming Language :: Python :: 3.13",
 ]
 keywords = [
     "ethereum",
@@ -48,18 +49,19 @@ Tracker = "https://github.com/BoboTiG/py-eip712-structs-ng/issues"
 [project.optional-dependencies]
 tests = [
   "eth-tester==0.12.0b1",
-  "mypy",
+  "mypy==1.10.1",
   "py-evm==0.10.1b1",
   "py-solc-x==2.0.3",
-  "pytest",
-  "pytest-cov",
-  "requests",
-  "ruff",
+  "pytest==8.2.2",
+  "pytest-cov==5.0.0",
+  "requests==2.32.3",
+  "ruff==0.5.1",
+  "setuptools==70.2.0",
   "web3>=6.3.0,<7",
 ]
 dev = [
-  "build",
-  "twine",
+  "build==1.2.1",
+  "twine==5.1.1",
 ]
 
 [tool.hatch.version]
diff --git a/src/eip712_structs/struct.py b/src/eip712_structs/struct.py
index f5fd4a6..0a76b3d 100644
--- a/src/eip712_structs/struct.py
+++ b/src/eip712_structs/struct.py
@@ -5,7 +5,7 @@
 import operator
 import re
 from collections import OrderedDict, defaultdict
-from collections.abc import Mapping
+from collections.abc import MutableMapping
 from typing import Any, NamedTuple
 
 from eth_utils.crypto import keccak
@@ -18,7 +18,7 @@ class OrderedAttributesMeta(type):
     """Metaclass to ensure struct attribute order is preserved."""
 
     @classmethod
-    def __prepare__(cls, name: str, bases: tuple[type, ...], /, **kwargs: Any) -> Mapping[str, object]:
+    def __prepare__(cls, name: str, bases: tuple[type, ...], /, **kwargs: Any) -> MutableMapping[str, object]:
         return OrderedDict()
 
 
diff --git a/src/tests/integration/contract_sources/_compile_contracts.py b/src/tests/integration/contract_sources/_compile_contracts.py
index 9920aae..e8d61ac 100644
--- a/src/tests/integration/contract_sources/_compile_contracts.py
+++ b/src/tests/integration/contract_sources/_compile_contracts.py
@@ -2,6 +2,7 @@
 Copied from web3.py/web3/_utils/contract_sources
 + custom changes (like optimizations to bypass contract code size over limit)
 """
+
 import argparse
 import contextlib
 import os