diff --git a/.pylintrc b/.pylintrc
index 4dc386d32..4e1bc8083 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -17,7 +17,7 @@ jobs=0
 # --enable=similarities". If you want to run only the classes checker, but have
 # no Warning level messages displayed, use"--disable=all --enable=classes
 # --disable=W"
-disable=redefined-builtin,C0330,duplicate-code,logging-format-interpolation,line-too-long,implicit-str-concat,logging-fstring-interpolation
+disable=redefined-builtin,C0330,duplicate-code,logging-format-interpolation,line-too-long,implicit-str-concat,logging-fstring-interpolation,unsubscriptable-object,inherit-non-class
 
 [REPORTS]
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 501a87cae..52b4938bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -36,6 +36,13 @@ The versions follow [semantic versioning](https://semver.org).
 ### Security
 -->
 
+## Unreleased - YYYY-MM-DD
+
+### Fixed
+
+- Declared dependency on `python-debian <= 0.1.38`. Later versions of the
+  dependency do not import on Windows.
+
 ## 0.12.1 - 2020-12-17
 
 ### Fixed
diff --git a/Makefile b/Makefile
index 88aececfc..dd140d90a 100644
--- a/Makefile
+++ b/Makefile
@@ -53,7 +53,7 @@ blackcheck: ## check with black
 
 .PHONY: black
 black: ## format with black
-	isort -y -s build -s dist
+	isort src/ tests/ *.py
 	black .
 
 .PHONY: reuse
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 3078c16fa..24e251618 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -4,22 +4,22 @@
 
 -r requirements.txt
 
-recommonmark==0.6.0
-sphinx_rtd_theme==0.4.3
-sphinx-autodoc-typehints==1.10.3
-sphinx==3.0.4
+recommonmark==0.7.1
+sphinx==3.4.3
+sphinx-autodoc-typehints==1.11.1
+sphinx-rtd-theme==0.5.1
 sphinxcontrib-apidoc==0.3.0
 
-black==19.10b0
-isort==4.3.21
-pylint==2.5.2
+black==20.8b1
+isort==5.7.0
+pylint==2.6.0
 
-pytest-cov==2.9.0
-pytest==5.4.2
-tox==3.15.1
+pytest==6.2.2
+pytest-cov==2.11.1
+tox==3.21.2
 
-bump2version==1.0.0
-pre-commit==2.4.0
-twine==3.1.1
+bump2version==1.0.1
+pre-commit==2.9.3
+twine==3.3.0
 
-wheel==0.34.2
+wheel==0.36.2
diff --git a/requirements.txt b/requirements.txt
index f80356e22..bbe6266f3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,5 +9,5 @@ license-expression==1.2
 python-debian==0.1.38
 requests==2.25.1
 
-setuptools==51.0.0
+setuptools==52.0.0
 setuptools-scm==5.0.1
diff --git a/setup.py b/setup.py
index 72a54666e..76ce3b2f0 100644
--- a/setup.py
+++ b/setup.py
@@ -15,8 +15,8 @@
 from setuptools.command.build_py import build_py
 
 requirements = [
-    # For parsing .reuse/dep5.
-    "python-debian",
+    # For parsing .reuse/dep5. TODO: Later versions do not work on Windows.
+    "python-debian <= 0.1.38",
     # For downloading from spdx/spdx-license-list-data. Could maybe use
     # standard library instead?
     "requests",
diff --git a/src/reuse/_util.py b/src/reuse/_util.py
index eca18c2af..bae01bf12 100644
--- a/src/reuse/_util.py
+++ b/src/reuse/_util.py
@@ -287,18 +287,20 @@ def __call__(self, string):
                 if not path.exists() and os.access(path.parent, os.W_OK):
                     return path
                 raise ArgumentTypeError(_("can't write to '{}'").format(path))
-        except OSError:
-            raise ArgumentTypeError(_("can't read or write '{}'").format(path))
+        except OSError as error:
+            raise ArgumentTypeError(
+                _("can't read or write '{}'").format(path)
+            ) from error
 
 
 def spdx_identifier(text: str) -> Expression:
     """argparse factory for creating SPDX expressions."""
     try:
         return _LICENSING.parse(text)
-    except (ExpressionError, ParseError):
+    except (ExpressionError, ParseError) as error:
         raise ArgumentTypeError(
             _("'{}' is not a valid SPDX expression, aborting").format(text)
-        )
+        ) from error
 
 
 def similar_spdx_identifiers(identifier: str) -> List[str]:
diff --git a/src/reuse/header.py b/src/reuse/header.py
index e54f4bd20..d84c94fc8 100644
--- a/src/reuse/header.py
+++ b/src/reuse/header.py
@@ -61,7 +61,7 @@
 _NEWLINE_PATTERN = re.compile(r"\n", re.MULTILINE)
 
 
-class _TextSections(NamedTuple):
+class _TextSections(NamedTuple):  # pylint: disable=too-few-public-methods
     """Used to split up text in three parts."""
 
     before: str
diff --git a/src/reuse/report.py b/src/reuse/report.py
index 4bd71b2d0..977532c88 100644
--- a/src/reuse/report.py
+++ b/src/reuse/report.py
@@ -46,7 +46,9 @@ def __call__(self, file_):
             return _MultiprocessingResult(file_, None, exc)
 
 
-class _MultiprocessingResult(NamedTuple):
+class _MultiprocessingResult(
+    NamedTuple
+):  # pylint: disable=too-few-public-methods
     """Result of :class:`MultiprocessingContainer`."""
 
     path: PathLike
diff --git a/tests/test_comment.py b/tests/test_comment.py
index e33f78dd3..be2775fad 100644
--- a/tests/test_comment.py
+++ b/tests/test_comment.py
@@ -83,8 +83,7 @@ def test_parse_comment_generic_multi(Style):
 
 
 def test_base_class_throws_errors():
-    """When trying to do much of anything with the base class, expect errors.
-    """
+    """When trying to do much of anything with the base class, expect errors."""
     with pytest.raises(CommentParseError):
         CommentStyle.parse_comment("hello")
     with pytest.raises(CommentCreateError):
@@ -166,8 +165,7 @@ def test_create_comment_python_force_multi():
 
 
 def test_parse_comment_python_strip_newlines():
-    """When given a comment, remove newlines before and after before parsing.
-    """
+    """When given a comment, remove newlines before and after before parsing."""
     text = dedent(
         """
 
diff --git a/tests/test_download.py b/tests/test_download.py
index a5c2140db..4a130eeaf 100644
--- a/tests/test_download.py
+++ b/tests/test_download.py
@@ -39,8 +39,7 @@ def test_download_404(monkeypatch):
 
 
 def test_download_exception(monkeypatch):
-    """If requests raises an exception itself, that exception is not escaped.
-    """
+    """If requests raises an exception itself, that exception is not escaped."""
 
     def raise_exception(_):
         raise requests.RequestException()
diff --git a/tests/test_header.py b/tests/test_header.py
index fe45586a1..85fb8d98b 100644
--- a/tests/test_header.py
+++ b/tests/test_header.py
@@ -340,8 +340,7 @@ def test_find_and_replace_separate_shebang():
 
 
 def test_find_and_replace_only_shebang():
-    """When the file only contains a shebang, keep it at the top of the file.
-    """
+    """When the file only contains a shebang, keep it at the top of the file."""
     spdx_info = SpdxInfo({"GPL-3.0-or-later"}, set())
     text = cleandoc(
         """