diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 244446a..8008011 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,10 +13,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out repo
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Set up Python 3.10
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: "3.10"
           cache: pip
@@ -34,7 +34,7 @@ jobs:
     if: github.event_name == 'release' && needs.tests.result == 'success'
     steps:
       - name: Check out repo
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Build and upload dist
         run: |
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 6f59f1e..1e133d1 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -7,14 +7,14 @@ exclude: tests/fixtures/raw_nb.py
 
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.1.5
+    rev: v0.3.0
     hooks:
       - id: ruff
         args: [--fix]
       - id: ruff-format
 
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.7.0
+    rev: v1.8.0
     hooks:
       - id: mypy
 
diff --git a/format_ipy_cells/helpers.py b/format_ipy_cells/helpers.py
index 4735677..f28c64c 100644
--- a/format_ipy_cells/helpers.py
+++ b/format_ipy_cells/helpers.py
@@ -96,3 +96,24 @@ def delete_last_cell_if_empty(text: str) -> str:
     """
     # \Z matches only at end of string
     return re.sub(r"(?m)\s+^# %%\s*\Z", r"\n", text)
+
+
+def single_blank_line_after_doc_string(text: str) -> str:
+    """Ensure single blank line between cell delimiter and preceding module doc string.
+
+    Added to avoid clash with ruff format. Started enforcing single blank line in 0.3.0.
+
+    --- before ---
+    '''module doc string.'''
+
+
+    # %%
+    some_code = 'here'
+
+    --- after ---
+    '''module doc string.'''
+
+    # %%
+    some_code = 'here'
+    """
+    return re.sub(r'(?m)(["\']{3})\n+(# %%)', r"\1\n\n\2", text)
diff --git a/format_ipy_cells/main.py b/format_ipy_cells/main.py
index f1385be..2212ac1 100644
--- a/format_ipy_cells/main.py
+++ b/format_ipy_cells/main.py
@@ -9,6 +9,7 @@
     format_comments_after_cell_delimiters,
     remove_empty_cells,
     remove_empty_lines_starting_cell,
+    single_blank_line_after_doc_string,
 )
 
 
@@ -39,6 +40,8 @@ def fix_file(filename: str) -> int:
 
     text = delete_last_cell_if_empty(text)
 
+    text = single_blank_line_after_doc_string(text)
+
     if orig_text != text:
         print(f"Rewriting {filename}")
 
diff --git a/pyproject.toml b/pyproject.toml
index 9472756..9c0d219 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -54,6 +54,7 @@ no_implicit_optional = false
 target-version = "py310"
 select = ["ALL"]
 ignore = [
+    "COM812", # trailing comma missing
     "D100",   # Missing docstring in public module
     "D104",   # Missing docstring in public package
     "D205",   # 1 blank line required between summary line and description
diff --git a/tests/fixtures/clean_nb.py b/tests/fixtures/clean_nb.py
index ea45f89..72e6cc6 100644
--- a/tests/fixtures/clean_nb.py
+++ b/tests/fixtures/clean_nb.py
@@ -1,3 +1,5 @@
+"""module doc string."""
+
 # %%
 foo = "hello"
 
@@ -9,6 +11,7 @@
 # %% a comment following a cell delimiter with too much space
 baz = 42
 
+"""longer comment"""
 
 # %% empty cell with comment (should not be removed despite empty)
 
diff --git a/tests/fixtures/raw_nb.py b/tests/fixtures/raw_nb.py
index 3d618f1..23ec433 100644
--- a/tests/fixtures/raw_nb.py
+++ b/tests/fixtures/raw_nb.py
@@ -1,3 +1,6 @@
+"""module doc string."""
+
+
 #  %%
 foo = "hello"
 #  %%a comment following a cell delimiter without space
@@ -5,7 +8,10 @@
 #  %%       a comment following a cell delimiter with too much space
 baz = 42
 
+"""longer comment"""
 
+  
+ 
 #  %%    empty cell with comment (should not be removed despite empty)
 
 
diff --git a/tests/test_main.py b/tests/test_main.py
index 1e27a73..37e40ad 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -1,3 +1,4 @@
+import difflib
 import filecmp
 import shutil
 from importlib.metadata import version
@@ -15,10 +16,18 @@ def test_main_format_cells(tmp_path: Path, capsys: pytest.CaptureFixture[str]) -
     shutil.copy2(clean_nb, clean_tmp := str(tmp_path / "clean_nb.py"))
 
     ret = main((raw_tmp, clean_tmp))
-
     assert ret == 1
-    assert filecmp.cmp(raw_tmp, clean_nb), "Formatted file has unexpected content"
-    assert filecmp.cmp(clean_tmp, clean_nb), "clean file should not have changed"
+
+    with open(clean_nb) as file, open(clean_tmp) as tmp_file:
+        clean_lines, tmp_lines = file.readlines(), tmp_file.readlines()
+    file_diff = "\n".join(difflib.unified_diff(clean_lines, tmp_lines))
+
+    assert filecmp.cmp(
+        raw_tmp, clean_nb, shallow=False
+    ), f"Formatted file has unexpected content:\n{file_diff}"
+    assert filecmp.cmp(
+        clean_tmp, clean_nb, shallow=False
+    ), "clean file should not have changed"
 
     out, err = capsys.readouterr()
     assert out == f"Rewriting {raw_tmp}\n"