diff --git a/libraries/src/Filesystem/File.php b/libraries/src/Filesystem/File.php
index c9aa02ec07ca9..435ead9ba9c3a 100644
--- a/libraries/src/Filesystem/File.php
+++ b/libraries/src/Filesystem/File.php
@@ -24,6 +24,8 @@
  * A File handling class
  *
  * @since  1.7.0
+ * @deprecated  4.4 will be removed in 6.0
+ *              Use Joomla\Filesystem\File instead.
  */
 class File
 {
@@ -69,6 +71,8 @@ public static function getExt($file)
      * @return  string  The file name without the extension
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::stripExt() instead.
      */
     public static function stripExt($file)
     {
@@ -83,6 +87,8 @@ public static function stripExt($file)
      * @return  string  The sanitised string
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::makeSafe() instead.
      */
     public static function makeSafe($file)
     {
@@ -111,6 +117,9 @@ public static function makeSafe($file)
      * @return  boolean  True on success
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::copy() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function copy($src, $dest, $path = null, $useStreams = false)
     {
@@ -187,6 +196,8 @@ public static function copy($src, $dest, $path = null, $useStreams = false)
      *                 FALSE from opcache_invalidate (like file not found).
      *
      * @since 4.0.1
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::invalidateFileCache() instead.
      */
     public static function invalidateFileCache($filepath, $force = true)
     {
@@ -210,6 +221,9 @@ public static function invalidateFileCache($filepath, $force = true)
      * @return boolean TRUE if we can proceed to use opcache_invalidate to flush a file from the OPCache
      *
      * @since 4.0.1
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::invalidateFileCache() instead.
+     *              This method will be removed without replacement.
      */
     public static function canFlushFileCache()
     {
@@ -238,6 +252,9 @@ public static function canFlushFileCache()
      * @return  boolean  True on success
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::delete() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function delete($file)
     {
@@ -311,6 +328,9 @@ public static function delete($file)
      * @return  boolean  True on success
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::move() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function move($src, $dest, $path = '', $useStreams = false)
     {
@@ -382,6 +402,8 @@ public static function move($src, $dest, $path = '', $useStreams = false)
      * @return  boolean  True on success
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::write() instead.
      */
     public static function write($file, $buffer, $useStreams = false)
     {
@@ -440,6 +462,7 @@ public static function write($file, $buffer, $useStreams = false)
      * @return  boolean  True on success
      *
      * @since   3.6.0
+     *
      */
     public static function append($file, $buffer, $useStreams = false)
     {
@@ -499,6 +522,9 @@ public static function append($file, $buffer, $useStreams = false)
      * @return  boolean  True on success
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\File::upload() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function upload($src, $dest, $useStreams = false, $allowUnsafe = false, $safeFileOptions = [])
     {
@@ -588,6 +614,8 @@ public static function upload($src, $dest, $useStreams = false, $allowUnsafe = f
      * @return  boolean  True if path is a file
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use is_file() instead.
      */
     public static function exists($file)
     {
diff --git a/libraries/src/Filesystem/FilesystemHelper.php b/libraries/src/Filesystem/FilesystemHelper.php
index 45a99be2ee064..a87e02b7adfa9 100644
--- a/libraries/src/Filesystem/FilesystemHelper.php
+++ b/libraries/src/Filesystem/FilesystemHelper.php
@@ -19,6 +19,8 @@
  * Holds support functions for the filesystem, particularly the stream
  *
  * @since  1.7.0
+ * @deprecated  4.4 will be removed in 6.0
+ *              Use Joomla\Filesystem\Helper instead.
  */
 class FilesystemHelper
 {
@@ -31,6 +33,8 @@ class FilesystemHelper
      *
      * @link    https://www.php.net/manual/en/function.filesize.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Helper::remotefsize() instead.
      */
     public static function remotefsize($url)
     {
@@ -114,6 +118,8 @@ public static function remotefsize($url)
      *
      * @link    https://www.php.net/manual/en/function.ftp-chmod.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Helper::ftpChmod() instead.
      */
     public static function ftpChmod($url, $mode)
     {
@@ -177,6 +183,8 @@ public static function ftpChmod($url, $mode)
      * @return  array
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Helper::getWriteModes() instead.
      */
     public static function getWriteModes()
     {
@@ -192,6 +200,8 @@ public static function getWriteModes()
      * @return  array  Streams
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Helper::getSupported() instead.
      */
     public static function getSupported()
     {
@@ -211,6 +221,8 @@ public static function getSupported()
      * @return  array
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Helper::getTransports() instead.
      */
     public static function getTransports()
     {
@@ -224,6 +236,8 @@ public static function getTransports()
      * @return  array
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Helper::getFilters() instead.
      */
     public static function getFilters()
     {
@@ -238,6 +252,8 @@ public static function getFilters()
      * @return  array
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Helper::getJStreams() instead.
      */
     public static function getJStreams()
     {
@@ -268,6 +284,8 @@ public static function getJStreams()
      * @return  boolean  True for a Joomla Stream
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Helper::isJoomlaStream() instead.
      */
     public static function isJoomlaStream($streamname)
     {
diff --git a/libraries/src/Filesystem/Folder.php b/libraries/src/Filesystem/Folder.php
index 828e95e9b97f6..cef115745c236 100644
--- a/libraries/src/Filesystem/Folder.php
+++ b/libraries/src/Filesystem/Folder.php
@@ -23,6 +23,8 @@
  * A Folder handling class
  *
  * @since  1.7.0
+ * @deprecated  4.4 will be removed in 6.0
+ *              Use Joomla\Filesystem\Folder instead.
  */
 abstract class Folder
 {
@@ -39,6 +41,8 @@ abstract class Folder
      *
      * @since   1.7.0
      * @throws  \RuntimeException
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::copy() instead.
      */
     public static function copy($src, $dest, $path = '', $force = false, $useStreams = false)
     {
@@ -159,6 +163,9 @@ public static function copy($src, $dest, $path = '', $force = false, $useStreams
      * @return  boolean  True if successful.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::create() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function create($path = '', $mode = 0755)
     {
@@ -272,6 +279,9 @@ public static function create($path = '', $mode = 0755)
      * @return  boolean  True on success.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::delete() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function delete($path)
     {
@@ -357,6 +367,9 @@ public static function delete($path)
      * @return  mixed  Error message on false or boolean true on success.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::move() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function move($src, $dest, $path = '', $useStreams = false)
     {
@@ -418,6 +431,8 @@ public static function move($src, $dest, $path = '', $useStreams = false)
      * @return  boolean  True if path is a folder
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use is_dir() instead.
      */
     public static function exists($path)
     {
@@ -438,6 +453,9 @@ public static function exists($path)
      * @return  array|boolean  Files in the given folder.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::files() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function files(
         $path,
@@ -491,6 +509,9 @@ public static function files(
      * @return  array  Folders in the given folder.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::folders() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function folders(
         $path,
@@ -540,6 +561,8 @@ public static function folders(
      * @return  array  Files.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::_items() instead.
      */
     protected static function _items($path, $filter, $recurse, $full, $exclude, $excludeFilterString, $findFiles)
     {
@@ -603,6 +626,8 @@ protected static function _items($path, $filter, $recurse, $full, $exclude, $exc
      * @return  array  Folders in the given folder.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::listFolderTree() instead.
      */
     public static function listFolderTree($path, $filter, $maxLevel = 3, $level = 0, $parent = 0)
     {
@@ -642,6 +667,8 @@ public static function listFolderTree($path, $filter, $maxLevel = 3, $level = 0,
      * @return  string  The sanitised string.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Folder::makeSafe() instead.
      */
     public static function makeSafe($path)
     {
diff --git a/libraries/src/Filesystem/Patcher.php b/libraries/src/Filesystem/Patcher.php
index 709d8a2929534..3d5f5505e9f77 100644
--- a/libraries/src/Filesystem/Patcher.php
+++ b/libraries/src/Filesystem/Patcher.php
@@ -20,6 +20,8 @@
  *
  * @link   http://sourceforge.net/projects/phppatcher/ This has been derived from the PhpPatcher version 0.1.1 written by Giuseppe Mazzotta
  * @since  3.0.0
+ * @deprecated  4.4 will be removed in 6.0
+ *              Use Joomla\Filesystem\Patcher instead.
  */
 class Patcher
 {
@@ -79,6 +81,8 @@ class Patcher
      * The constructor is protected to force the use of FilesystemPatcher::getInstance()
      *
      * @since   3.0.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::__construct() instead.
      */
     protected function __construct()
     {
@@ -90,6 +94,8 @@ protected function __construct()
      * @return  Patcher  an instance of the patcher
      *
      * @since   3.0.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::getInstance() instead.
      */
     public static function getInstance()
     {
@@ -106,6 +112,8 @@ public static function getInstance()
      * @return  Patcher  This object for chaining
      *
      * @since   3.0.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::reset() instead.
      */
     public function reset()
     {
@@ -124,6 +132,8 @@ public function reset()
      *
      * @since   3.0.0
      * @throws  \RuntimeException
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::apply() instead.
      */
     public function apply()
     {
@@ -208,6 +218,8 @@ public function apply()
      * @return  Patcher  $this for chaining
      *
      * @since   3.0.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::addFile() instead.
      */
     public function addFile($filename, $root = JPATH_BASE, $strip = 0)
     {
@@ -224,6 +236,8 @@ public function addFile($filename, $root = JPATH_BASE, $strip = 0)
      * @return  Patcher  $this for chaining
      *
      * @since   3.0.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::add() instead.
      */
     public function add($udiff, $root = JPATH_BASE, $strip = 0)
     {
@@ -244,6 +258,8 @@ public function add($udiff, $root = JPATH_BASE, $strip = 0)
      * @return  array  The lines of the inputdestination file
      *
      * @since   3.0.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::splitLines() instead.
      */
     protected static function splitLines($data)
     {
@@ -263,6 +279,8 @@ protected static function splitLines($data)
      *
      * @since   3.0.0
      * @throws  \RuntimeException
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::findHeader() instead.
      */
     protected static function findHeader(&$lines, &$src, &$dst)
     {
@@ -320,6 +338,8 @@ protected static function findHeader(&$lines, &$src, &$dst)
      *
      * @since   3.0.0
      * @throws  \RuntimeException
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::findHunk() instead.
      */
     protected static function findHunk(&$lines, &$srcLine, &$srcSize, &$dstLine, &$dstSize)
     {
@@ -367,6 +387,8 @@ protected static function findHunk(&$lines, &$srcLine, &$srcSize, &$dstLine, &$d
      *
      * @since   3.0.0
      * @throws  \RuntimeException
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::applyHunk() instead.
      */
     protected function applyHunk(&$lines, $src, $dst, $srcLine, $srcSize, $dstLine, $dstSize)
     {
@@ -468,6 +490,8 @@ protected function applyHunk(&$lines, $src, $dst, $srcLine, $srcSize, $dstLine,
      * @return  array  The lines of the source file
      *
      * @since   3.0.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::getSource() instead.
      */
     protected function &getSource($src)
     {
@@ -491,6 +515,8 @@ protected function &getSource($src)
      * @return  array  The lines of the destination file
      *
      * @since   3.0.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Patcher::getDestination() instead.
      */
     protected function &getDestination($dst, $src)
     {
diff --git a/libraries/src/Filesystem/Path.php b/libraries/src/Filesystem/Path.php
index 658011deab79e..faf981503763a 100644
--- a/libraries/src/Filesystem/Path.php
+++ b/libraries/src/Filesystem/Path.php
@@ -22,6 +22,8 @@
  * A Path handling class
  *
  * @since  1.7.0
+ * @deprecated  4.4 will be removed in 6.0
+ *              Use Joomla\Filesystem\Path instead.
  */
 class Path
 {
@@ -33,6 +35,8 @@ class Path
      * @return  boolean  True if path can have mode changed.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::canChmod() instead.
      */
     public static function canChmod($path)
     {
@@ -59,6 +63,8 @@ public static function canChmod($path)
      * @return  boolean  True if successful [one fail means the whole operation failed].
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::setPermissions() instead.
      */
     public static function setPermissions($path, $filemode = '0644', $foldermode = '0755')
     {
@@ -110,6 +116,9 @@ public static function setPermissions($path, $filemode = '0644', $foldermode = '
      * @return  string  Filesystem permissions.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::getPermissions() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public static function getPermissions($path)
     {
@@ -145,6 +154,8 @@ public static function getPermissions($path)
      *
      * @throws  \Exception
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::check() instead.
      */
     public static function check($path)
     {
@@ -183,6 +194,8 @@ public static function check($path)
      *
      * @throws  \UnexpectedValueException
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::clean() instead.
      */
     public static function clean($path, $ds = DIRECTORY_SEPARATOR)
     {
@@ -229,6 +242,8 @@ public static function clean($path, $ds = DIRECTORY_SEPARATOR)
      * @return  boolean  True if the php script owns the path passed.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::isOwner() instead.
      */
     public static function isOwner($path)
     {
@@ -275,6 +290,8 @@ public static function isOwner($path)
      * @return  mixed   The full path and file name for the target file, or boolean false if the file is not found in any of the paths.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::find() instead.
      */
     public static function find($paths, $file)
     {
@@ -322,6 +339,8 @@ public static function find($paths, $file)
      * @return  string  The resolved path
      *
      * @since   3.9.25
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::resolve() instead.
      */
     public static function resolve($path)
     {
@@ -364,6 +383,8 @@ public static function resolve($path)
      * @return  string
      *
      * @since   3.10.7
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Path::removeRoot() instead.
      */
     public static function removeRoot($message, $rootDirectory = null)
     {
diff --git a/libraries/src/Filesystem/Stream.php b/libraries/src/Filesystem/Stream.php
index ed2cbc4631fea..0b58c0c952c73 100644
--- a/libraries/src/Filesystem/Stream.php
+++ b/libraries/src/Filesystem/Stream.php
@@ -30,6 +30,8 @@
  * @link   https://www.php.net/manual/en/filters.php Stream Filters
  * @link   https://www.php.net/manual/en/transports.php Socket Transports (used by some options, particularly HTTP proxy)
  * @since  1.7.0
+ * @deprecated  4.4 will be removed in 6.0
+ *              Use Joomla\Filesystem\Stream instead.
  */
 class Stream extends CMSObject
 {
@@ -146,6 +148,8 @@ class Stream extends CMSObject
      * @param   array   $context      The context options (optional).
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::__construct() instead.
      */
     public function __construct($writeprefix = '', $readprefix = '', $context = [])
     {
@@ -159,6 +163,8 @@ public function __construct($writeprefix = '', $readprefix = '', $context = [])
      * Destructor
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::__destruct() instead.
      */
     public function __destruct()
     {
@@ -185,6 +191,9 @@ public function __destruct()
      * @return  boolean
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::open() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function open(
         $filename,
@@ -295,6 +304,9 @@ public function open(
      * @return  boolean
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::close() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function close()
     {
@@ -352,6 +364,9 @@ public function close()
      * @return  boolean
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::eof() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function eof()
     {
@@ -395,6 +410,9 @@ public function eof()
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::filesize() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function filesize()
     {
@@ -455,6 +473,9 @@ public function filesize()
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::gets() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function gets($length = 0)
     {
@@ -507,6 +528,9 @@ public function gets($length = 0)
      *
      * @link    https://www.php.net/manual/en/function.fread.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::read() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function read($length = 0)
     {
@@ -595,6 +619,9 @@ public function read($length = 0)
      *
      * @link    https://www.php.net/manual/en/function.fseek.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::seek() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function seek($offset, $whence = SEEK_SET)
     {
@@ -643,6 +670,9 @@ public function seek($offset, $whence = SEEK_SET)
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::tell() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function tell()
     {
@@ -700,6 +730,9 @@ public function tell()
      *
      * @link    https://www.php.net/manual/en/function.fwrite.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::write() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function write(&$string, $length = 0, $chunk = 0)
     {
@@ -766,6 +799,9 @@ public function write(&$string, $length = 0, $chunk = 0)
      * @return  boolean
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::chmod() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function chmod($filename = '', $mode = 0)
     {
@@ -825,6 +861,9 @@ public function chmod($filename = '', $mode = 0)
      *
      * @link    https://www.php.net/manual/en/function.stream-get-meta-data.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::get_meta_data() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function get_meta_data()
     {
@@ -844,6 +883,8 @@ public function get_meta_data()
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::_buildContext() instead.
      */
     public function _buildContext()
     {
@@ -866,6 +907,8 @@ public function _buildContext()
      *
      * @link    https://www.php.net/stream_context_create
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::setContextOptions() instead.
      */
     public function setContextOptions($context)
     {
@@ -885,6 +928,8 @@ public function setContextOptions($context)
      * @link    https://www.php.net/stream_context_create Stream Context Creation
      * @link    https://www.php.net/manual/en/context.php Context Options for various streams
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::addContextEntry() instead.
      */
     public function addContextEntry($wrapper, $name, $value)
     {
@@ -902,6 +947,8 @@ public function addContextEntry($wrapper, $name, $value)
      *
      * @link    https://www.php.net/stream_context_create
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::deleteContextEntry() instead.
      */
     public function deleteContextEntry($wrapper, $name)
     {
@@ -932,6 +979,9 @@ public function deleteContextEntry($wrapper, $name)
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::applyContextToStream() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function applyContextToStream()
     {
@@ -967,6 +1017,9 @@ public function applyContextToStream()
      *
      * @link    https://www.php.net/manual/en/function.stream-filter-append.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::appendFilter() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function appendFilter($filterName, $readWrite = STREAM_FILTER_READ, $params = [])
     {
@@ -1004,6 +1057,9 @@ public function appendFilter($filterName, $readWrite = STREAM_FILTER_READ, $para
      *
      * @link    https://www.php.net/manual/en/function.stream-filter-prepend.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::prependFilter() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function prependFilter($filterName, $readWrite = STREAM_FILTER_READ, $params = [])
     {
@@ -1041,6 +1097,9 @@ public function prependFilter($filterName, $readWrite = STREAM_FILTER_READ, $par
      * @return  boolean   Result of operation
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::removeFilter() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function removeFilter(&$resource, $byindex = false)
     {
@@ -1077,6 +1136,9 @@ public function removeFilter(&$resource, $byindex = false)
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::copy() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function copy($src, $dest, $context = null, $usePrefix = true, $relative = false)
     {
@@ -1127,6 +1189,9 @@ public function copy($src, $dest, $context = null, $usePrefix = true, $relative
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::move() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function move($src, $dest, $context = null, $usePrefix = true, $relative = false)
     {
@@ -1172,6 +1237,9 @@ public function move($src, $dest, $context = null, $usePrefix = true, $relative
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::delete() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function delete($filename, $context = null, $usePrefix = true, $relative = false)
     {
@@ -1215,6 +1283,9 @@ public function delete($filename, $context = null, $usePrefix = true, $relative
      * @return  mixed
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::upload() instead.
+     *              The framework class throws Exceptions in case of error which you have to catch.
      */
     public function upload($src, $dest, $context = null, $usePrefix = true, $relative = false)
     {
@@ -1237,6 +1308,8 @@ public function upload($src, $dest, $context = null, $usePrefix = true, $relativ
      * @return  boolean
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::writeFile() instead.
      */
     public function writeFile($filename, &$buffer)
     {
@@ -1262,6 +1335,8 @@ public function writeFile($filename, &$buffer)
      * @return  string
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::_getFilename() instead.
      */
     public function _getFilename($filename, $mode, $usePrefix, $relative)
     {
@@ -1295,6 +1370,8 @@ public function _getFilename($filename, $mode, $usePrefix, $relative)
      * @return  resource  File handler
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream::getFileHandle() instead.
      */
     public function getFileHandle()
     {
diff --git a/libraries/src/Filesystem/Streams/StreamString.php b/libraries/src/Filesystem/Streams/StreamString.php
index 1f0bf2e34237d..fa718e331ec49 100644
--- a/libraries/src/Filesystem/Streams/StreamString.php
+++ b/libraries/src/Filesystem/Streams/StreamString.php
@@ -20,6 +20,8 @@
  * you would normally use a regular stream wrapper
  *
  * @since  1.7.0
+ * @deprecated  4.4 will be removed in 6.0
+ *              Use Joomla\Filesystem\Stream\StringWrapper instead.
  */
 class StreamString
 {
@@ -100,6 +102,8 @@ class StreamString
      * @return  boolean
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::stream_open() instead.
      */
     public function stream_open($path, $mode, $options, &$openedPath)
     {
@@ -123,6 +127,8 @@ public function stream_open($path, $mode, $options, &$openedPath)
      *
      * @link    https://www.php.net/manual/en/streamwrapper.stream-stat.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::stream_stat instead.
      */
     public function stream_stat()
     {
@@ -139,6 +145,8 @@ public function stream_stat()
      *
      * @link    https://www.php.net/manual/en/streamwrapper.url-stat.php
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::url_stat() instead.
      */
     public function url_stat($path, $flags = 0)
     {
@@ -172,10 +180,11 @@ public function url_stat($path, $flags = 0)
      *
      * @return  string
      *
-     * @since   1.7.0
-     *
      * @link    https://www.php.net/manual/en/streamwrapper.stream-read.php
-     */
+     * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::stream_read() instead.
+ */
     public function stream_read($count)
     {
         $result = substr($this->currentString, $this->pos, $count);
@@ -193,6 +202,8 @@ public function stream_read($count)
      *
      * @since   1.7.0
      * @note    Updating the string is not supported.
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::stream_write() instead.
      */
     public function stream_write($data)
     {
@@ -206,6 +217,8 @@ public function stream_write($data)
      * @return  integer  The position
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::stream_tell() instead.
      */
     public function stream_tell()
     {
@@ -218,6 +231,8 @@ public function stream_tell()
      * @return  boolean  True if at end of field.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::stream_eof() instead.
      */
     public function stream_eof()
     {
@@ -237,6 +252,8 @@ public function stream_eof()
      * @return  boolean  True on success.
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::stream_seek() instead.
      */
     public function stream_seek($offset, $whence)
     {
@@ -274,6 +291,8 @@ public function stream_seek($offset, $whence)
      *
      * @since   1.7.0
      * @note    Data storage is not supported
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Stream\StringWrapper::stream_flush() instead.
      */
     public function stream_flush()
     {
diff --git a/libraries/src/Filesystem/Support/StringController.php b/libraries/src/Filesystem/Support/StringController.php
index 46f85bdd33ff7..f718eae838391 100644
--- a/libraries/src/Filesystem/Support/StringController.php
+++ b/libraries/src/Filesystem/Support/StringController.php
@@ -17,6 +17,8 @@
  * String Controller
  *
  * @since  1.7.0
+ * @deprecated  4.4 will be removed in 6.0
+ *              Use Joomla\Filesystem\Support\StringController instead.
  */
 class StringController
 {
@@ -26,6 +28,8 @@ class StringController
      * @return  array
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Support\StringController::getArray() instead.
      */
     public function _getArray()
     {
@@ -43,6 +47,8 @@ public function _getArray()
      * @return  void
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Support\StringController::createRef() instead.
      */
     public function createRef($reference, &$string)
     {
@@ -58,6 +64,8 @@ public function createRef($reference, &$string)
      * @return  mixed  False if not set, reference if it exists
      *
      * @since   1.7.0
+     * @deprecated  4.4 will be removed in 6.0
+     *              Use Joomla\Filesystem\Support\StringController::getRef() instead.
      */
     public function getRef($reference)
     {