diff --git a/Doxyfile b/Doxyfile
index 7d2a63a..2ec9054 100644
--- a/Doxyfile
+++ b/Doxyfile
@@ -38,7 +38,7 @@ PROJECT_NAME           = "Arduino List Library"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 3.0.0
+PROJECT_NUMBER         = 3.0.1
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/library.json b/library.json
index 614cb80..b616dc8 100644
--- a/library.json
+++ b/library.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://raw.githubusercontent.com/platformio/platformio-core/develop/platformio/assets/schema/library.json",
   "name": "List",
-  "version": "3.0.0",
+  "version": "3.0.1",
   "description": "The Ultimate Collection of Lists. This library extends the Arduino ecosystem with the functionality of several easy-to-use lists for numerous purposes.",
   "keywords": [
     "arduino",
diff --git a/library.properties b/library.properties
index 4dcf179..dfec90f 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=List
-version=3.0.0
+version=3.0.1
 author=Niklas Kaaf <nkaaf@protonmail.com>
 maintainer=Niklas Kaaf <nkaaf@protonmail.com>
 sentence=The Ultimate Collection of Lists
diff --git a/src/AbstractList.hpp b/src/AbstractList.hpp
index afa0617..9c814ed 100644
--- a/src/AbstractList.hpp
+++ b/src/AbstractList.hpp
@@ -5,7 +5,7 @@
  * easy-to-use list implementations. They are specially designed and optimized
  * for different purposes.
  *
- * Copyright (C) 2021-2023  Niklas Kaaf
+ * Copyright (C) 2021-2024  Niklas Kaaf
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -26,6 +26,8 @@
 #ifndef LIST_ABSTRACT_LIST_HPP
 #define LIST_ABSTRACT_LIST_HPP
 
+#include <stddef.h>
+
 /*!
  * @brief   Abstract class from which all lists can be derived.
  *