From 90b62ba50617840e49ccf0e4618c6aa291ed62dd Mon Sep 17 00:00:00 2001
From: Filipe-Bicho <37207570+Filipe-Bicho@users.noreply.github.com>
Date: Tue, 14 Aug 2018 15:36:35 +0200
Subject: [PATCH 1/2] Return-Path Email is not used

E-mail Return-Path is not used because it only uses the last forced e-mail address, so this code change gives priority to the e-mail address that is already stored in the parameters and therefore the return path mail will be set correctly.
---
 src/Transport/Sendmail.php | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/Transport/Sendmail.php b/src/Transport/Sendmail.php
index 821c94e3..5a927f68 100644
--- a/src/Transport/Sendmail.php
+++ b/src/Transport/Sendmail.php
@@ -258,12 +258,16 @@ protected function prepareParameters(Mail\Message $message)
             return;
         }
 
-        $parameters = (string) $this->parameters;
+        $parameters = '';
+        $priorityParameters = '';
+
+        if ($this->parameters)
+            $priorityParameters = (string) $this->parameters;
 
         $sender = $message->getSender();
         if ($sender instanceof AddressInterface) {
             $parameters .= ' -f' . \escapeshellarg($sender->getEmail());
-            return $parameters;
+            return $parameters . $priorityParameters;
         }
 
         $from = $message->getFrom();
@@ -271,10 +275,10 @@ protected function prepareParameters(Mail\Message $message)
             $from->rewind();
             $sender      = $from->current();
             $parameters .= ' -f' . \escapeshellarg($sender->getEmail());
-            return $parameters;
+            return $parameters . $priorityParameters;
         }
 
-        return $parameters;
+        return $parameters . $priorityParameters;
     }
 
     /**

From f69185ee246c3aa5931ec964c98f0105e5db5b49 Mon Sep 17 00:00:00 2001
From: Filipe-Bicho <37207570+Filipe-Bicho@users.noreply.github.com>
Date: Tue, 14 Aug 2018 16:30:37 +0200
Subject: [PATCH 2/2] Update Sendmail.php

---
 src/Transport/Sendmail.php | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/Transport/Sendmail.php b/src/Transport/Sendmail.php
index 5a927f68..a5227149 100644
--- a/src/Transport/Sendmail.php
+++ b/src/Transport/Sendmail.php
@@ -258,8 +258,8 @@ protected function prepareParameters(Mail\Message $message)
             return;
         }
 
-        $parameters = '';
-        $priorityParameters = '';
+        $parameters = null;
+        $priorityParameters = null;
 
         if ($this->parameters)
             $priorityParameters = (string) $this->parameters;
@@ -267,7 +267,7 @@ protected function prepareParameters(Mail\Message $message)
         $sender = $message->getSender();
         if ($sender instanceof AddressInterface) {
             $parameters .= ' -f' . \escapeshellarg($sender->getEmail());
-            return $parameters . $priorityParameters;
+            return trim($parameters . $priorityParameters);
         }
 
         $from = $message->getFrom();
@@ -275,10 +275,10 @@ protected function prepareParameters(Mail\Message $message)
             $from->rewind();
             $sender      = $from->current();
             $parameters .= ' -f' . \escapeshellarg($sender->getEmail());
-            return $parameters . $priorityParameters;
+            return trim($parameters . $priorityParameters);
         }
 
-        return $parameters . $priorityParameters;
+        return trim($parameters . $priorityParameters);
     }
 
     /**