diff --git a/.gitignore b/.gitignore
index c49449b..3953b2a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -146,3 +146,4 @@ dmypy.json
 
 tests/data/tmp_*
 docs/data/tmp_*
+local/*
diff --git a/pyproject.toml b/pyproject.toml
index 6528966..9fbb232 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "tsdf"
-version = "0.5.1"
+version = "0.5.2"
 description = "A Python library that provides methods for encoding and decoding TSDF (Time Series Data Format) data, which allows you to easily create, manipulate and serialize TSDF files in your Python code."
 authors = ["Peter Kok <p.kok@esciencecenter.nl>",
             "Pablo Rodríguez <p.rodriguez-sanchez@esciencecenter.nl>",
diff --git a/src/tsdf/numpy_utils.py b/src/tsdf/numpy_utils.py
index 4d91308..e7f6ea0 100644
--- a/src/tsdf/numpy_utils.py
+++ b/src/tsdf/numpy_utils.py
@@ -61,6 +61,7 @@ def bytes_tsdf_to_numpy(n_bits: int):
     "<": "little",
     ">": "big",
     "=": sys.byteorder,
+    "|": "not applicable",
 }
 """ Supported endianness values. """
 
@@ -79,6 +80,7 @@ def endianness_numpy_to_tsdf(data: np.ndarray) -> str:
 _map_to_numpy_endianness = {
     "little": "<",
     "big": ">",
+    "not applicable": "|",
 }
 """ Supported endianness values. """