diff --git a/doc/admin.md b/doc/admin.md
index 5f280af224..fa36c245b3 100644
--- a/doc/admin.md
+++ b/doc/admin.md
@@ -56,6 +56,10 @@ Configure how often Mail keeps users' mailboxes updated in the background in sec
 ```
 
 ### Use php-mail for sending mail
+
+> [!WARNING]
+> Support for using php-mail will be removed with Mail 4.2
+
 You can use the php-mail function to send mails. This is needed for some webhosters (1&1 (1und1)):
 ```php
 'app.mail.transport' => 'php-mail'
diff --git a/lib/SMTP/SmtpClientFactory.php b/lib/SMTP/SmtpClientFactory.php
index 3d63195fba..e5c84bae4a 100644
--- a/lib/SMTP/SmtpClientFactory.php
+++ b/lib/SMTP/SmtpClientFactory.php
@@ -43,10 +43,6 @@ public function __construct(IConfig $config,
 	 */
 	public function create(Account $account): Horde_Mail_Transport {
 		$mailAccount = $account->getMailAccount();
-		$transport = $this->config->getSystemValue('app.mail.transport', 'smtp');
-		if ($transport === 'php-mail') {
-			return new Horde_Mail_Transport_Mail();
-		}
 
 		$decryptedPassword = null;
 		if ($mailAccount->getOutboundPassword() !== null) {
diff --git a/lib/SystemConfig.php b/lib/SystemConfig.php
deleted file mode 100644
index b16b9bca90..0000000000
--- a/lib/SystemConfig.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-/**
- * SPDX-FileCopyrightText: 2020 Nextcloud GmbH and Nextcloud contributors
- * SPDX-License-Identifier: AGPL-3.0-or-later
- */
-
-namespace OCA\Mail;
-
-use OCP\IConfig;
-
-class SystemConfig {
-	/** @var IConfig */
-	private $config;
-
-	public function __construct(IConfig $config) {
-		$this->config = $config;
-	}
-
-	public function hasWorkingSmtp(): bool {
-		return $this->config->getSystemValue('app.mail.transport', 'smtp') === 'smtp';
-	}
-}