diff --git a/CHANGELOG.md b/CHANGELOG.md
index 949e1a6..416ce22 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,21 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Don't error when there's a datetime in the header https://github.com/OpenDataServices/flatten-tool/issues/438
 
+## [0.24.3]
+
+### Fixed
+
+- Ignore null characters in the input CSV file when reading configuration from the header rows
+  https://github.com/OpenDataServices/flatten-tool/pull/446
+
+## [0.24.2] - 2024-06-12
+
+### Fixed
+
+- Rename `_get_column_letter` import to `get_colunmn_letter` for compatibility
+  with latest openpyxl
+  https://github.com/OpenDataServices/flatten-tool/issues/443
+
 ## [0.24.1] - 2024-02-09
 
 ### Fixed
diff --git a/flattentool/input.py b/flattentool/input.py
index 80d007d..524b4c2 100644
--- a/flattentool/input.py
+++ b/flattentool/input.py
@@ -24,7 +24,7 @@
 except ImportError:
     SHAPELY_AND_GEOJSON_LIBRARIES_AVAILABLE = False
 
-from openpyxl.utils.cell import _get_column_letter
+from openpyxl.utils.cell import get_column_letter
 
 from flattentool.exceptions import DataErrorWarning
 from flattentool.i18n import _
@@ -386,11 +386,11 @@ def do_unflatten(self):
                                     actual_heading,
                                     ", ".join(
                                         [
-                                            _get_column_letter(x + 1)
+                                            get_column_letter(x + 1)
                                             for x in ignoring[:-1]
                                         ]
                                     ),
-                                    _get_column_letter(ignoring[-1] + 1),
+                                    get_column_letter(ignoring[-1] + 1),
                                     sheet_name,
                                 ),
                                 DataErrorWarning,
@@ -404,8 +404,8 @@ def do_unflatten(self):
                                     )
                                 ).format(
                                     actual_heading,
-                                    _get_column_letter(ignoring[0] + 1),
-                                    _get_column_letter(ignoring[1] + 1),
+                                    get_column_letter(ignoring[0] + 1),
+                                    get_column_letter(ignoring[1] + 1),
                                     sheet_name,
                                 ),
                                 DataErrorWarning,
@@ -419,7 +419,7 @@ def do_unflatten(self):
                                     )
                                 ).format(
                                     actual_heading,
-                                    _get_column_letter(ignoring[0] + 1),
+                                    get_column_letter(ignoring[0] + 1),
                                     sheet_name,
                                 ),
                                 DataErrorWarning,
@@ -445,7 +445,7 @@ def do_unflatten(self):
                     else:
                         cells[header] = Cell(
                             line[header],
-                            (sheet_name, _get_column_letter(k + 1), j + 2, heading),
+                            (sheet_name, get_column_letter(k + 1), j + 2, heading),
                         )
                 unflattened = unflatten_main_with_parser(
                     self.parser,
@@ -677,7 +677,7 @@ def get_sheet_configuration(self, sheet_name):
         with open(
             os.path.join(self.input_name, sheet_name + ".csv"), encoding=self.encoding
         ) as main_sheet_file:
-            r = csvreader(main_sheet_file)
+            r = csvreader(NullCharacterFilter(main_sheet_file))
             heading_row = next(r)
         if len(heading_row) > 0 and heading_row[0] == "#":
             return heading_row[1:]
@@ -740,7 +740,7 @@ def get_sheet_headings(self, sheet_name):
         if self.vertical_orientation:
             return [
                 cell.value
-                for cell in worksheet[_get_column_letter(skip_rows + 1)][
+                for cell in worksheet[get_column_letter(skip_rows + 1)][
                     configuration_line:
                 ]
             ]
@@ -777,7 +777,7 @@ def get_sheet_lines(self, sheet_name):
 
         worksheet = self.workbook[self.sheet_names_map[sheet_name]]
         if self.vertical_orientation:
-            header_row = worksheet[_get_column_letter(skip_rows + 1)]
+            header_row = worksheet[get_column_letter(skip_rows + 1)]
             remaining_rows = worksheet.iter_cols(min_col=skip_rows + header_rows + 1)
             if configuration_line:
                 header_row = header_row[1:]
diff --git a/setup.py b/setup.py
index f65e663..518fb51 100644
--- a/setup.py
+++ b/setup.py
@@ -43,7 +43,7 @@ def run(self):
 
 setup(
     name="flattentool",
-    version="0.24.1",
+    version="0.24.2",
     author="Open Data Services",
     author_email="code@opendataservices.coop",
     packages=["flattentool"],