diff --git a/fhem/FHEM/00_MQTT2_CLIENT.pm b/fhem/FHEM/00_MQTT2_CLIENT.pm
index 8f6ec4ff3..0130ff72d 100644
--- a/fhem/FHEM/00_MQTT2_CLIENT.pm
+++ b/fhem/FHEM/00_MQTT2_CLIENT.pm
@@ -48,6 +48,7 @@ MQTT2_CLIENT_Initialize($)
     msgBeforeDisconnect
     mqttVersion:3.1.1,3.1
     privacy:0,1
+    qosMaxQueueLength
     rawEvents
     subscriptions
     SSL
@@ -99,6 +100,7 @@ MQTT2_CLIENT_doinit($)
   if($hash->{connecting} == 1) {
     my $usr = AttrVal($name, "username", "");
     my ($err, $pwd) = getKeyValue($name);
+    $pwd = undef if($usr eq "");
     if($err) {
       Log 1, "ERROR: $err";
       return;
@@ -130,7 +132,7 @@ MQTT2_CLIENT_doinit($)
       InternalTimer(gettimeofday()+$keepalive,"MQTT2_CLIENT_keepalive",$hash,0);
     }
 
-  ############################## SUBSCRIBE
+  ############################## SUBSCRIBE & RESEND Non-Acked
   } elsif($hash->{connecting} == 2) {
     my $s = AttrVal($name, "subscriptions", "#");
     if($s eq "setByTheProgram") {
@@ -145,7 +147,24 @@ MQTT2_CLIENT_doinit($)
       MQTT2_CLIENT_calcRemainingLength(length($msg)).$msg, 0, 1);
     $hash->{connecting} = 3;
 
+
+  } elsif($hash->{connecting} == 3) {
+    my $onc = AttrVal($name, "msgAfterConnect", "");
+    delete($hash->{connecting});
+    MQTT2_CLIENT_doPublish($hash, $2, $3, $1, 1)
+      if($onc && $onc =~ m/^(-r\s)?([^\s]*)\s*(.*)$/);
+
+    if($hash->{qosQueue} && @{$hash->{qosQueue}}) {
+      my $pa = $hash->{qosQueue};
+      $hash->{qosQueue} = [];
+      for(my $i1=0; $i1<@{$pa}; $i1++) {
+        my $r = $pa->[$i1];
+        MQTT2_CLIENT_doPublish($hash, $r->[0], $r->[1], $r->[2], 0);
+      }
+    }
+
   }
+
   return undef;
 }
 
@@ -233,8 +252,20 @@ MQTT2_CLIENT_Attr(@)
     delete($hash->{authError});
     MQTT2_CLIENT_Disco($hash);
   }
+
+  if($attrName eq "qosMaxQueueLength") {
+    if($type eq "set" && $param[0] ne "0") {
+      return "qosMaxQueueLength must be an integer" if($param[0] !~ m/^\d+$/);
+      $hash->{qosMaxQueueLength} = $param[0];
+      $hash->{qosQueue} = [];
+    } else {
+      delete $hash->{qosQueue};
+      delete $hash->{qosMaxQueueLength};
+    }
+  }
+
   return undef;
-} 
+}
 
 sub
 MQTT2_CLIENT_Set($@)
@@ -345,14 +376,12 @@ MQTT2_CLIENT_Read($@)
       MQTT2_CLIENT_Disco($hash);
       return;
     }
-  } elsif($cpt eq "PUBACK")   { # ignore it
-  } elsif($cpt eq "SUBACK")   {
-    if($hash->{connecting}) {
-      delete($hash->{connecting});
-      my $onc = AttrVal($name, "msgAfterConnect", "");
-      MQTT2_CLIENT_doPublish($hash, $2, $3, $1, 1)
-        if($onc && $onc =~ m/^(-r\s)?([^\s]*)\s*(.*)$/);
-    }
+
+  } elsif($cpt eq "PUBACK") { 
+    shift(@{$hash->{qosQueue}}) if($hash->{qosQueue});
+
+  } elsif($cpt eq "SUBACK") {
+    MQTT2_CLIENT_doinit($hash) if($hash->{connecting});
 
   } elsif($cpt eq "PINGRESP") {
     delete($hash->{waitingForPingRespSince});
@@ -402,10 +431,21 @@ MQTT2_CLIENT_doPublish($@)
   my $name = $hash->{NAME};
   return if(IsDisabled($name));
   $val = "" if(!defined($val));
-  my $msg = pack("C", $retain ? 0x31:0x30).
-            MQTT2_CLIENT_calcRemainingLength(2+length($topic)+length($val)).
+
+  my $hdr = 0x30;
+  my $pi = "";
+  $hdr += 1 if($retain);
+  if(defined($hash->{qosQueue}) &&
+     @{$hash->{qosQueue}} < $hash->{qosMaxQueueLength}) {
+    $hdr += 2; # QoS:1
+    push(@{$hash->{qosQueue}}, [$topic,$val,$retain]);
+    $pi = "FM"; # Packet Identifier, if QoS > 0
+  }
+  my $msg = pack("C", $hdr).
+            MQTT2_CLIENT_calcRemainingLength(2+length($topic)+length($val)+
+                                length($pi)).
             pack("n", length($topic)).
-            $topic.$val;
+            $topic.$pi.$val;
   MQTT2_CLIENT_send($hash, $msg, $immediate)
 }
 
@@ -618,6 +658,14 @@ MQTT2_CLIENT_getStr($$)
       If the optional -r is specified, then the publish sets the retain flag.
       </li></br>
 
+    <a name="MQTT_CLIENTqosMaxQueueLength"></a>
+    <li>qosMaxQueueLength &lt;number&gt;<br>
+      if set to a nonzero value, messages are published with QoS=1, and are
+      kept in a memory-only buffer until acknowledged by the server.
+      If there is no connection to the server, up to &lt;number&gt; messages
+      are queued, and resent when the connection is esablished.
+      </li></br>
+      
     <a name="MQTT_CLIENTrawEvents"></a>
     <li>rawEvents &lt;topic-regexp&gt;<br>
       send all messages as events attributed to this MQTT2_CLIENT instance.