diff --git a/src/Module/Api/Mastodon/Accounts/UpdateCredentials.php b/src/Module/Api/Mastodon/Accounts/UpdateCredentials.php
index d3f4c15fe0..b2a23cf424 100644
--- a/src/Module/Api/Mastodon/Accounts/UpdateCredentials.php
+++ b/src/Module/Api/Mastodon/Accounts/UpdateCredentials.php
@@ -21,8 +21,9 @@
 
 namespace Friendica\Module\Api\Mastodon\Accounts;
 
+use Friendica\Core\Logger;
 use Friendica\Module\BaseApi;
-use Friendica\Util\Network;
+use Friendica\Util\HTTPInputData;
 
 /**
  * @see https://docs.joinmastodon.org/methods/accounts/
@@ -34,9 +35,10 @@ class UpdateCredentials extends BaseApi
 		self::login(self::SCOPE_WRITE);
 		$uid = self::getCurrentUserID();
 
-		$data = Network::postdata();
+		$data = HTTPInputData::process();
+
+		Logger::info('Patch data', ['data' => $data]);
 
-		// @todo Parse the raw data that is in the "multipart/form-data" format
 		self::unsupported('patch');
 	}
 }
diff --git a/src/Util/HTTPInputData.php b/src/Util/HTTPInputData.php
new file mode 100644
index 0000000000..c1dba263c2
--- /dev/null
+++ b/src/Util/HTTPInputData.php
@@ -0,0 +1,295 @@
+<?php
+/**
+ * @copyright Copyright (C) 2010-2021, the Friendica project
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Util;
+
+/**
+ * Derived from the work of Reid Johnson <https://codereview.stackexchange.com/users/4020/reid-johnson>
+ * @see https://codereview.stackexchange.com/questions/69882/parsing-multipart-form-data-in-php-for-put-requests
+ */
+class HTTPInputData
+{
+	public static function process()
+	{
+		$content_parts = explode(';', static::getContentType());
+
+		$boundary = '';
+		$encoding = '';
+
+		$content_type = array_shift($content_parts);
+
+		foreach ($content_parts as $part) {
+			if (strpos($part, 'boundary') !== false) {
+				$part = explode('=', $part, 2);
+				if (!empty($part[1])) {
+					$boundary = '--' . $part[1];
+				}
+			} elseif (strpos($part, 'charset') !== false) {
+				$part = explode('=', $part, 2);
+				if (!empty($part[1])) {
+					$encoding = $part[1];
+				}
+			}
+			if ($boundary !== '' && $encoding !== '') {
+				break;
+			}
+		}
+
+		if ($content_type == 'multipart/form-data') {
+			return self::fetchFromMultipart($boundary);
+		}
+
+		// can be handled by built in PHP functionality
+		$content = static::getPhpInputContent();
+
+		$variables = json_decode($content, true);
+
+		if (empty($variables)) {
+			parse_str($content, $variables);
+		}
+
+		return ['variables' => $variables, 'files' => []];
+	}
+
+	private static function fetchFromMultipart(string $boundary)
+	{
+		$result = ['variables' => [], 'files' => []];
+
+		$stream = static::getPhpInputStream();
+
+		$sanity = fgets($stream, strlen($boundary) + 5);
+
+		// malformed file, boundary should be first item
+		if (rtrim($sanity) !== $boundary) {
+			return $result;
+		}
+
+		$raw_headers = '';
+
+		while (($chunk = fgets($stream)) !== false) {
+			if ($chunk === $boundary) {
+				continue;
+			}
+
+			if (!empty(trim($chunk))) {
+				$raw_headers .= $chunk;
+				continue;
+			}
+
+			$result = self::parseRawHeader($stream, $raw_headers, $boundary, $result);
+
+			$raw_headers = '';
+		}
+
+		fclose($stream);
+
+		return $result;
+	}
+
+	private static function parseRawHeader($stream, string $raw_headers, string $boundary, array $result)
+	{
+		$variables = $result['variables'];
+		$files     = $result['files'];
+
+		$headers = [];
+
+		foreach (explode("\r\n", $raw_headers) as $header) {
+			if (strpos($header, ':') === false) {
+				continue;
+			}
+			list($name, $value) = explode(':', $header, 2);
+
+			$headers[strtolower($name)] = ltrim($value, ' ');
+		}
+
+		if (!isset($headers['content-disposition'])) {
+			return ['variables' => $variables, 'files' => $files];
+		}
+
+		if (!preg_match('/^(.+); *name="([^"]+)"(; *filename="([^"]+)")?/', $headers['content-disposition'], $matches)) {
+			return ['variables' => $variables, 'files' => $files];
+		}
+
+		$name     = $matches[2];
+		$filename = $matches[4] ?? '';
+
+		if (!empty($filename)) {
+			$files[$name] = static::fetchFileData($stream, $boundary, $headers, $filename);
+			return ['variables' => $variables, 'files' => $files];
+		} else {
+			$variables = self::fetchVariables($stream, $boundary, $headers, $name, $variables);
+		}
+
+		return ['variables' => $variables, 'files' => $files];
+	}
+
+	protected static function fetchFileData($stream, string $boundary, array $headers, string $filename)
+	{
+		$error = UPLOAD_ERR_OK;
+
+		if (isset($headers['content-type'])) {
+			$tmp = explode(';', $headers['content-type']);
+
+			$contentType = $tmp[0];
+		} else {
+			$contentType = 'unknown';
+		}
+
+		$tmpnam     = tempnam(ini_get('upload_tmp_dir'), 'php');
+		$fileHandle = fopen($tmpnam, 'wb');
+
+		if ($fileHandle === false) {
+			$error = UPLOAD_ERR_CANT_WRITE;
+		} else {
+			$lastLine = null;
+			while (($chunk = fgets($stream, 8096)) !== false && strpos($chunk, $boundary) !== 0) {
+				if ($lastLine !== null) {
+					if (fwrite($fileHandle, $lastLine) === false) {
+						$error = UPLOAD_ERR_CANT_WRITE;
+						break;
+					}
+				}
+				$lastLine = $chunk;
+			}
+
+			if ($lastLine !== null && $error !== UPLOAD_ERR_CANT_WRITE) {
+				if (fwrite($fileHandle, rtrim($lastLine, "\r\n")) === false) {
+					$error = UPLOAD_ERR_CANT_WRITE;
+				}
+			}
+		}
+
+		return [
+			'name'     => $filename,
+			'type'     => $contentType,
+			'tmp_name' => $tmpnam,
+			'error'    => $error,
+			'size'     => filesize($tmpnam)
+		];
+	}
+
+	private static function fetchVariables($stream, string $boundary, array $headers, string $name, array $variables)
+	{
+		$fullValue = '';
+		$lastLine  = null;
+
+		while (($chunk = fgets($stream)) !== false && strpos($chunk, $boundary) !== 0) {
+			if ($lastLine !== null) {
+				$fullValue .= $lastLine;
+			}
+
+			$lastLine = $chunk;
+		}
+
+		if ($lastLine !== null) {
+			$fullValue .= rtrim($lastLine, "\r\n");
+		}
+
+		if (isset($headers['content-type'])) {
+			$encoding = '';
+
+			foreach (explode(';', $headers['content-type']) as $part) {
+				if (strpos($part, 'charset') !== false) {
+					$part = explode($part, '=', 2);
+					if (isset($part[1])) {
+						$encoding = $part[1];
+					}
+					break;
+				}
+			}
+
+			if ($encoding !== '' && strtoupper($encoding) !== 'UTF-8' && strtoupper($encoding) !== 'UTF8') {
+				$tmp = mb_convert_encoding($fullValue, 'UTF-8', $encoding);
+				if ($tmp !== false) {
+					$fullValue = $tmp;
+				}
+			}
+		}
+
+		$fullValue = $name . '=' . $fullValue;
+
+		$tmp = [];
+		parse_str($fullValue, $tmp);
+
+		return self::expandVariables(explode('[', $name), $variables, $tmp);
+	}
+
+	private static function expandVariables(array $names, $variables, array $values)
+	{
+		if (!is_array($variables)) {
+			return $values;
+		}
+
+		$name = rtrim(array_shift($names), ']');
+		if ($name !== '') {
+			$name = $name . '=p';
+
+			$tmp = [];
+			parse_str($name, $tmp);
+
+			$tmp  = array_keys($tmp);
+			$name = reset($tmp);
+		}
+
+		if ($name === '') {
+			$variables[] = reset($values);
+		} elseif (isset($variables[$name]) && isset($values[$name])) {
+			$variables[$name] = self::expandVariables($names, $variables[$name], $values[$name]);
+		} elseif (isset($values[$name])) {
+			$variables[$name] = $values[$name];
+		}
+
+		return $variables;
+	}
+
+	/**
+	 * Returns the current PHP input stream
+	 * Mainly used for test doubling
+	 *
+	 * @return false|resource
+	 */
+	protected static function getPhpInputStream()
+	{
+		return fopen('php://input', 'rb');
+	}
+
+	/**
+	 * Returns the content of the current PHP input
+	 * Mainly used for test doubling
+	 *
+	 * @return false|string
+	 */
+	protected static function getPhpInputContent()
+	{
+		return file_get_contents('php://input');
+	}
+
+	/**
+	 * Returns the content type string of the current call
+	 * Mainly used for test doubling
+	 *
+	 * @return false|string
+	 */
+	protected static function getContentType()
+	{
+		return $_SERVER['CONTENT_TYPE'] ?? 'application/x-www-form-urlencoded';
+	}
+}
diff --git a/tests/Util/HTTPInputDataDouble.php b/tests/Util/HTTPInputDataDouble.php
new file mode 100644
index 0000000000..391b9c82bb
--- /dev/null
+++ b/tests/Util/HTTPInputDataDouble.php
@@ -0,0 +1,97 @@
+<?php
+/**
+ * @copyright Copyright (C) 2010-2021, the Friendica project
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Test\Util;
+
+use Friendica\Util\HTTPInputData;
+
+/**
+ * This class is used to enable testability for HTTPInputData
+ * It overrides the two PHP input functionality with custom content
+ */
+class HTTPInputDataDouble extends HTTPInputData
+{
+	/** @var false|resource */
+	protected static $injectedStream = false;
+	/** @var false|string */
+	protected static $injectedContent = false;
+	/** @var false|string */
+	protected static $injectedContentType = false;
+
+	/**
+	 * injects the PHP input stream for a test
+	 *
+	 * @param false|resource $stream
+	 */
+	public static function setPhpInputStream($stream)
+	{
+		self::$injectedStream = $stream;
+	}
+
+	/**
+	 * injects the PHP input content for a test
+	 *
+	 * @param false|string $content
+	 */
+	public static function setPhpInputContent($content)
+	{
+		self::$injectedContent = $content;
+	}
+
+	/**
+	 * injects the PHP input content type for a test
+	 *
+	 * @param false|string $contentType
+	 */
+	public static function setPhpInputContentType($contentType)
+	{
+		self::$injectedContentType = $contentType;
+	}
+
+	/** {@inheritDoc} */
+	protected static function getPhpInputStream()
+	{
+		return static::$injectedStream;
+	}
+
+	/** {@inheritDoc} */
+	protected static function getPhpInputContent()
+	{
+		return static::$injectedContent;
+	}
+
+	/** {@inheritDoc} */
+	protected static function getContentType()
+	{
+		return static::$injectedContentType;
+	}
+
+	protected static function fetchFileData($stream, string $boundary, array $headers, string $filename)
+	{
+		$data = parent::fetchFileData($stream, $boundary, $headers, $filename);
+		if (!empty($data['tmp_name'])) {
+			unlink($data['tmp_name']);
+			$data['tmp_name'] = $data['name'];
+		}
+
+		return $data;
+	}
+}
diff --git a/tests/datasets/http/form-urlencoded-json.httpinput b/tests/datasets/http/form-urlencoded-json.httpinput
new file mode 100644
index 0000000000..4d7ca0f3e4
--- /dev/null
+++ b/tests/datasets/http/form-urlencoded-json.httpinput
@@ -0,0 +1 @@
+{"media_ids":[],"sensitive":false,"status":"Test Status","visibility":"private","spoiler_text":"Title"}
diff --git a/tests/datasets/http/form-urlencoded.httpinput b/tests/datasets/http/form-urlencoded.httpinput
new file mode 100644
index 0000000000..3a71aff994
--- /dev/null
+++ b/tests/datasets/http/form-urlencoded.httpinput
@@ -0,0 +1 @@
+title=Test2
\ No newline at end of file
diff --git a/tests/datasets/http/multipart-file.httpinput b/tests/datasets/http/multipart-file.httpinput
new file mode 100644
index 0000000000..a1bc0de31f
Binary files /dev/null and b/tests/datasets/http/multipart-file.httpinput differ
diff --git a/tests/datasets/http/multipart.httpinput b/tests/datasets/http/multipart.httpinput
new file mode 100644
index 0000000000..b1498e476f
--- /dev/null
+++ b/tests/datasets/http/multipart.httpinput
@@ -0,0 +1,50 @@
+--43395968-f65c-437e-b536-5b33e3e3c7e5
+Content-Disposition: form-data; name="display_name"
+Content-Transfer-Encoding: binary
+Content-Type: multipart/form-data; charset=utf-8
+Content-Length: 9
+
+User Name
+--43395968-f65c-437e-b536-5b33e3e3c7e5
+Content-Disposition: form-data; name="note"
+Content-Transfer-Encoding: binary
+Content-Type: multipart/form-data; charset=utf-8
+Content-Length: 8
+
+About me
+--43395968-f65c-437e-b536-5b33e3e3c7e5
+Content-Disposition: form-data; name="locked"
+Content-Transfer-Encoding: binary
+Content-Type: multipart/form-data; charset=utf-8
+Content-Length: 5
+
+false
+--43395968-f65c-437e-b536-5b33e3e3c7e5
+Content-Disposition: form-data; name="fields_attributes[0][name]"
+Content-Transfer-Encoding: binary
+Content-Type: multipart/form-data; charset=utf-8
+Content-Length: 10
+
+variable 1
+--43395968-f65c-437e-b536-5b33e3e3c7e5
+Content-Disposition: form-data; name="fields_attributes[0][value]"
+Content-Transfer-Encoding: binary
+Content-Type: multipart/form-data; charset=utf-8
+Content-Length: 7
+
+value 1
+--43395968-f65c-437e-b536-5b33e3e3c7e5
+Content-Disposition: form-data; name="fields_attributes[1][name]"
+Content-Transfer-Encoding: binary
+Content-Type: multipart/form-data; charset=utf-8
+Content-Length: 10
+
+variable 2
+--43395968-f65c-437e-b536-5b33e3e3c7e5
+Content-Disposition: form-data; name="fields_attributes[1][value]"
+Content-Transfer-Encoding: binary
+Content-Type: multipart/form-data; charset=utf-8
+Content-Length: 7
+
+value 2
+--43395968-f65c-437e-b536-5b33e3e3c7e5--
diff --git a/tests/src/Util/HTTPInputDataTest.php b/tests/src/Util/HTTPInputDataTest.php
new file mode 100644
index 0000000000..5e8fd228fd
--- /dev/null
+++ b/tests/src/Util/HTTPInputDataTest.php
@@ -0,0 +1,152 @@
+<?php
+/**
+ * @copyright Copyright (C) 2010-2021, the Friendica project
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Test\src\Util;
+
+use Friendica\Test\MockedTest;
+use Friendica\Test\Util\HTTPInputDataDouble;
+use Friendica\Util\HTTPInputData;
+
+/**
+ * Testing HTTPInputData
+ *
+ * @see	HTTPInputData
+ */
+class HTTPInputDataTest extends MockedTest
+{
+	/**
+	 * Returns the data stream for the unit test
+	 * Each array element of the first hierarchy represents one test run
+	 * Each array element of the second hierarchy represents the parameters, passed to the test function
+	 *
+	 * @return array[]
+	 */
+	public function dataStream()
+	{
+		return [
+			'multipart' => [
+				'contenttype' => 'multipart/form-data;boundary=43395968-f65c-437e-b536-5b33e3e3c7e5;charset=utf8',
+				'input'       => file_get_contents(__DIR__ . '/../../datasets/http/multipart.httpinput'),
+				'expected'    => [
+					'variables' => [
+						'display_name'      => 'User Name',
+						'note'              => 'About me',
+						'locked'            => 'false',
+						'fields_attributes' => [
+							0 => [
+								'name'  => 'variable 1',
+								'value' => 'value 1',
+							],
+							1 => [
+								'name'  => 'variable 2',
+								'value' => 'value 2',
+							]
+						]
+					],
+					'files' => []
+				]
+			],
+			'multipart-file' => [
+				'contenttype' => 'multipart/form-data;boundary=6d4d5a40-651a-4468-a62e-5a6ca2bf350d;charset=utf8',
+				'input'       => file_get_contents(__DIR__ . '/../../datasets/http/multipart-file.httpinput'),
+				'expected'    => [
+					'variables' => [
+						'display_name'      => 'Vorname Nachname',
+						'note'              => 'About me',
+						'fields_attributes' => [
+							0 => [
+								'name'  => 'variable 1',
+								'value' => 'value 1',
+							],
+							1 => [
+								'name'  => 'variable 2',
+								'value' => 'value 2',
+							]
+						]
+					],
+					'files' => [
+						'avatar' => [
+							'name'     => '8ZUCS34Y5XNH',
+							'type'     => 'image/png',
+							'tmp_name' => '8ZUCS34Y5XNH',
+							'error'    => 0,
+							'size'     => 349330
+						],
+						'header' => [
+							'name'     => 'V2B6Z1IICGPM',
+							'type'     => 'image/png',
+							'tmp_name' => 'V2B6Z1IICGPM',
+							'error'    => 0,
+							'size'     => 1323635
+						]
+					]
+				]
+			],
+			'form-urlencoded' => [
+				'contenttype' => 'application/x-www-form-urlencoded;charset=utf8',
+				'input'       => file_get_contents(__DIR__ . '/../../datasets/http/form-urlencoded.httpinput'),
+				'expected'    => [
+					'variables' => [
+						'title' => 'Test2',
+					],
+					'files' => []
+				]
+			],
+			'form-urlencoded-json' => [
+				'contenttype' => 'application/x-www-form-urlencoded;charset=utf8',
+				'input'       => file_get_contents(__DIR__ . '/../../datasets/http/form-urlencoded-json.httpinput'),
+				'expected'    => [
+					'variables' => [
+						'media_ids'    => [],
+						'sensitive'    => false,
+						'status'       => 'Test Status',
+						'visibility'   => 'private',
+						'spoiler_text' => 'Title'
+					],
+					'files' => []
+				]
+			]
+		];
+	}
+
+	/**
+	 * Tests the HTTPInputData::process() method
+	 *
+	 * @param string $contentType The content typer of the transmitted data
+	 * @param string $input       The input, we got from the data stream
+	 * @param array  $expected    The expected output
+	 *
+	 * @dataProvider dataStream
+	 * @see HTTPInputData::process()
+	 */
+	public function testHttpInput(string $contentType, string $input, array $expected)
+	{
+		HTTPInputDataDouble::setPhpInputContentType($contentType);
+		HTTPInputDataDouble::setPhpInputContent($input);
+		$stream = fopen('php://memory', 'r+');
+		fwrite($stream, $input);
+		rewind($stream);
+
+		HTTPInputDataDouble::setPhpInputStream($stream);
+		$output = HTTPInputDataDouble::process();
+		$this->assertEqualsCanonicalizing($expected, $output);
+	}
+}