diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7bd105f..e17b62d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [4.0.1] - 2025-06-23
+### Fixed
+-  `write_xml` - Remove encoding kwarg to fix `binary mode doesn't take an encoding argument`
+
 ## [4.0.0] - 2025-06-22
 ### Breaking
 - Renamed argument `filepath` of methods `write_xml`, `TestSuite.write`, and `JUnitXml.write`
diff --git a/junitparser/__init__.py b/junitparser/__init__.py
index 2282b95..0491244 100644
--- a/junitparser/__init__.py
+++ b/junitparser/__init__.py
@@ -16,7 +16,7 @@
     TestSuite,
 )
 
-version = "4.0.0"
+version = "4.0.1"
 
 __all__ = [
     "Attr",
diff --git a/junitparser/junitparser.py b/junitparser/junitparser.py
index bbf7046..74973e6 100644
--- a/junitparser/junitparser.py
+++ b/junitparser/junitparser.py
@@ -33,7 +33,7 @@ def write_xml(obj, file_or_filename: Optional[Union[str, IO]] = None, *, pretty:
         xml = parseString(text)  # nosec
         content = xml.toprettyxml(encoding="utf-8")
         if isinstance(file_or_filename, str):
-            with open(file_or_filename, encoding="utf-8", mode="wb") as xmlfile:
+            with open(file_or_filename, mode="wb") as xmlfile:
                 xmlfile.write(content)
         else:
             if isinstance(file_or_filename, io.TextIOWrapper):