diff --git a/doc/releases/release-notes-4.0.rst b/doc/releases/release-notes-4.0.rst
index 8b9ede8f11eba2..492057c551d391 100644
--- a/doc/releases/release-notes-4.0.rst
+++ b/doc/releases/release-notes-4.0.rst
@@ -1367,6 +1367,7 @@ Libraries / Subsystems
 
     * :ref:`POSIX_DEVICE_IO <posix_option_group_device_io>`
     * :ref:`POSIX_SIGNALS <posix_option_group_signals>`
+    * :ref:`POSIX_FILE_SYSTEM_R <posix_option_group_file_system_r>`
 
   * Added support for the following Options:
 
@@ -1381,6 +1382,7 @@ Libraries / Subsystems
   * :ref:`_POSIX_THREAD_SAFE_FUNCTIONS <posix_option_thread_safe_functions>` improvements:
 
     * Support for :c:func:`asctime_r`, :c:func:`ctime_r`, and :c:func:`localtime_r`.
+    * Added stub for :c:func:`getpwnam_r`, :c:func:`getpwuid_r`, :c:func:`getgrgid_r` and :c:func:`getgrnam_r`.
 
   * :ref:`POSIX_THREADS_BASE <posix_option_group_threads_base>` improvements:
 
diff --git a/doc/services/portability/posix/option_groups/index.rst b/doc/services/portability/posix/option_groups/index.rst
index 300fd9118e3ca2..e1e2b930cc803a 100644
--- a/doc/services/portability/posix/option_groups/index.rst
+++ b/doc/services/portability/posix/option_groups/index.rst
@@ -258,6 +258,19 @@ Enable this option group with :kconfig:option:`CONFIG_POSIX_FILE_SYSTEM`.
     unlink(), yes
     utime(),
 
+.. _posix_option_group_file_system_r:
+
+POSIX_FILE_SYSTEM_R
++++++++++++++++++++
+
+Enable this option with :kconfig:option:`CONFIG_POSIX_FILE_SYSTEM_R`.
+
+.. csv-table:: POSIX_FILE_SYSTEM_R
+   :header: API, Supported
+   :widths: 50,10
+
+    readdir_r(), yes
+
 .. _posix_option_group_mapped_files:
 
 POSIX_MAPPED_FILES