diff --git a/lib/class.ISPConfig.inc.php b/lib/class.ISPConfig.inc.php
index 78586571e1a8b156bac5258a033502ccd9215279..8e03c7aa1b003c84202c6cfd0c1944e75a6d89e2 100644
--- a/lib/class.ISPConfig.inc.php
+++ b/lib/class.ISPConfig.inc.php
@@ -291,11 +291,6 @@ Possible arguments are:
 		try {
 			$os = ISPConfigBaseOS::getOSVersion();
 			
-			if(!self::wantsAmavis() && (!isset($_GET['channel']) || $_GET['channel'] !== 'dev')) {
-				ISPConfigLog::info('<lightred>NOTE:</lightred> Installing ISPConfig stable with rspamd is not supported until 3.1.15 release (due to rspamd support). Please use --channel=dev to install stable-3.1 git development branch or --use-amavis to use amavis instead of rspamd.', true);
-				exit;
-			}
-			
 			ISPConfigLog::info('Starting perfect server setup for ' . $os['NAME'], true);
 			$installer = ISPConfigBaseOS::getOSInstance();
 			$installer->runPerfectSetup();
diff --git a/lib/os/class.ISPConfigBaseOS.inc.php b/lib/os/class.ISPConfigBaseOS.inc.php
index a87954034b6fdf3312d3a3b414105339bb7272fa..ac64fe9d939918b6c8a00190a9b63279d639a2a7 100644
--- a/lib/os/class.ISPConfigBaseOS.inc.php
+++ b/lib/os/class.ISPConfigBaseOS.inc.php
@@ -86,7 +86,7 @@ class ISPConfigBaseOS {
 		while($result === false && $tries > 0) {
 			$return_var = 0;
 			$output = array();
-			$tmp = exec($cmd, $output, $return_var);
+			exec($cmd, $output, $return_var);
 			ISPConfigLog::debug('CMD: ' . $cmd . ' returned code ' . $return_var);
 			if($return_var === 0 || (!empty($returncodes_ok) && is_array($returncodes_ok) && in_array($return_var, $returncodes_ok, true))) {
 				$result = implode("\n", $output);
@@ -99,6 +99,23 @@ class ISPConfigBaseOS {
 		return $result;
 	}
 	
+	public function passthru($cmd, $returncodes_ok = array(), $tries = 1, $retry_codes = null) {
+		$result = false;
+		while($result === false && $tries > 0) {
+			$return_var = 0;
+			passthru($cmd, $return_var);
+			ISPConfigLog::debug('CMD: ' . $cmd . ' returned code ' . $return_var);
+			if($return_var === 0 || (!empty($returncodes_ok) && is_array($returncodes_ok) && in_array($return_var, $returncodes_ok, true))) {
+				$result = true;
+			} elseif(is_array($retry_codes) && !empty($retry_codes) && !in_array($return_var, $retry_codes)) {
+				break;
+			}
+			$tries--;
+		}
+		
+		return $result;
+	}
+	
 	protected function addLines($file, $entries, $add_if_existing = false) {
 		if(!is_array($entries)) {
 			$entries = array($entries);
diff --git a/lib/os/class.ISPConfigDebianOS.inc.php b/lib/os/class.ISPConfigDebianOS.inc.php
index 9fc0944503db09b3f02a7c96ee15ccd433563fca..44ce32f4d1cfd054cabad20fb5591f4bf916d490 100644
--- a/lib/os/class.ISPConfigDebianOS.inc.php
+++ b/lib/os/class.ISPConfigDebianOS.inc.php
@@ -1123,7 +1123,11 @@ mailman-unsubscribe:  "|/var/lib/mailman/mail/mailman unsubscribe mailman"';
 			$cmd .= ' ; wget -O ispconfig.tar.gz "https://www.ispconfig.org/downloads/ISPConfig-3-stable.tar.gz" >/dev/null 2>&1 ; tar xzf ispconfig.tar.gz';
 		}
 		$cmd .= ' ; cd ispconfig3_install ; cd install ; php -q install.php ' . $ai_argument . ' 2>&1 ; cd /tmp ; rm -rf ispconfig3_install 2>&1';
-		$result = $this->exec($cmd);
+		if(ISPConfig::wantsInteractive()) {
+			$result = $this->passthru($cmd);
+		} else {
+			$result = $this->exec($cmd);
+		}
 		if($result === false) {
 			throw new ISPConfigOSException('Command ' . $cmd . ' failed.');
 		}