diff --git a/ch-wirth.ch.zone b/ch-wirth.ch.zone
index c9cab91..bd16203 100644
--- a/ch-wirth.ch.zone
+++ b/ch-wirth.ch.zone
@@ -2,7 +2,7 @@ $TTL 4h
 $ORIGIN ch-wirth.ch.
 
 @  1D  IN	 SOA ns1.nbit.ch. hostmaster.nbit.ch. (
-			      2023090802 ; serial
+			      2023090803 ; serial
 			      3H ; refresh
 			      120; retry
 			      2w ; expire
@@ -15,7 +15,7 @@ $ORIGIN ch-wirth.ch.
        IN  MX  10 mail.ch-wirth.ch. ; Mail Exchange Fallback
        IN  A      135.181.95.247
 
-       IN  TXT "v=spf1 ip4:213.200.229.13 -all"
+       IN  TXT "v=spf1 ip4:213.200.229.13 mx -all"
 
 
 ; server host definitions