diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 5fe9e3a..402b2ef 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
 - repo: https://github.com/pre-commit/pre-commit-hooks
-  rev: v4.5.0
+  rev: v4.6.0
   hooks:
   - id: trailing-whitespace
     args: [--markdown-linebreak-ext=md]
@@ -8,7 +8,7 @@ repos:
   - id: check-yaml
   # ----- Python formatting -----
 - repo: https://github.com/astral-sh/ruff-pre-commit
-  rev: v0.3.4
+  rev: v0.4.2
   hooks:
       # Run ruff linter.
   - id: ruff
@@ -19,12 +19,12 @@ repos:
   - id: ruff-format
   # ----- repo maintenance -----
 - repo: https://github.com/macisamuele/language-formatters-pre-commit-hooks
-  rev: v2.12.0
+  rev: v2.13.0
   hooks:
   - id: pretty-format-yaml
     args: [--autofix, --indent, '2']
 - repo: https://github.com/tox-dev/pyproject-fmt
-  rev: 1.7.0
+  rev: 1.8.0
   hooks:
   - id: pyproject-fmt
 - repo: https://github.com/abravalheri/validate-pyproject
diff --git a/action.yml b/action.yml
index 8b5b485..ac0d34c 100644
--- a/action.yml
+++ b/action.yml
@@ -41,7 +41,7 @@ runs:
   steps:
   - name: create environment file
     run: >
-      pip3 install tomli packaging pyyaml &&
+      pip3 install tomli packaging pyyaml $PIP_OPTIONS &&
       python3 $GITHUB_ACTION_PATH/pydeps2env/generate_environment.py ${{ inputs.files }}
       --output ${{ inputs.output }}
       --channels ${{ inputs.channels }}
@@ -49,6 +49,8 @@ runs:
       --build_system ${{ inputs.build_system }}
       --pip ${{ inputs.pip }}
     shell: bash
+    env:
+      PIP_OPTIONS: ${{ runner.os == 'macOS' && '--break-system-packages' || '' }}
   - name: show environment file
     run: cat ${{ inputs.output }}
     shell: bash
diff --git a/pydeps2env/environment.py b/pydeps2env/environment.py
index bdee184..5b59460 100644
--- a/pydeps2env/environment.py
+++ b/pydeps2env/environment.py
@@ -5,12 +5,21 @@
 from pathlib import Path
 from collections import defaultdict
 import configparser
-import tomli as tomllib
+import sys
 import yaml
-import warnings
 from io import StringIO, BytesIO
 from warnings import warn
 
+if sys.version_info < (3, 11):
+    import tomli as tomllib
+else:
+    import tomllib
+
+
+def clean_list(item: list, sort: bool = True) -> list:
+    """Remove duplicate entries from a list."""
+    pass
+
 
 def split_extras(filename: str) -> tuple[str, set]:
     """Split extras requirements indicated in []."""
@@ -264,7 +273,7 @@ def export(
                 outfile.writelines("\n".join(deps))
         else:
             if p.suffix not in [".yaml", ".yml"]:
-                warnings.warn(
+                warn(
                     f"Unknown environment format `{p.suffix}`, generating conda yaml output."
                 )
             with open(p, "w") as outfile:
diff --git a/pyproject.toml b/pyproject.toml
index 2dc648f..d7aca76 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,7 +31,7 @@ dynamic = [
 dependencies = [
   "packaging",
   "pyyaml",
-  "tomli",
+  'tomli; python_version < "3.11"',
 ]
 [project.optional-dependencies]
 test = [