From 93b483a5da9cf25b7711e3469cf8366bdc9b9ad4 Mon Sep 17 00:00:00 2001
From: arturwwl <32646237+arturwwl@users.noreply.github.com>
Date: Mon, 19 Sep 2022 22:46:10 +0200
Subject: [PATCH] fix MIME-Version header (#66)

---
 email.go | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/email.go b/email.go
index 4b1eda6..6652301 100644
--- a/email.go
+++ b/email.go
@@ -497,8 +497,10 @@ func (email *Email) AddHeader(header string, values ...string) *Email {
 		return email
 	}
 
-	// Set header to correct canonical Mime
-	header = textproto.CanonicalMIMEHeaderKey(header)
+	if header != "MIME-Version" {
+		// Set header to correct canonical Mime
+		header = textproto.CanonicalMIMEHeaderKey(header)
+	}
 
 	switch header {
 	case "Sender":