diff --git a/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js b/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
index 166f68381..605a8baa1 100644
--- a/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
+++ b/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
@@ -68,12 +68,21 @@ module.exports = function(RED) {
     }
 
     /**
-     * Test a topic string is valid
+     * Test a topic string is valid for subscription
      * @param {string} topic
      * @returns `true` if it is a valid topic
      */
     function isValidSubscriptionTopic(topic) {
-        return /^(#$|(\+|[^+#]*)(\/(\+|[^+#]*))*(\/(\+|#|[^+#]*))?$)/.test(topic)
+        return /^(#$|(\+|[^+#]*)(\/(\+|[^+#]*))*(\/(\+|#|[^+#]*))?$)/.test(topic);
+    }
+
+    /**
+     * Test a topic string is valid for publishing
+     * @param {string} topic
+     * @returns `true` if it is a valid topic
+     */
+    function isValidPublishTopic(topic) {
+        return !/[\+#\b\f\n\r\t\v\0]/.test(topic);
     }
 
     /**
@@ -288,7 +297,7 @@ module.exports = function(RED) {
                         //TODO: delete msg.responseTopic - to prevent it being resent?
                     }
                 }
-                topicOK = topicOK && !/[\+#\b\f\n\r\t\v\0]/.test(msg.topic);
+                topicOK = topicOK && isValidPublishTopic(msg.topic);
 
                 if (topicOK) {
                     node.brokerConn.publish(msg, done); // send the message
@@ -362,7 +371,7 @@ module.exports = function(RED) {
                     node.brokerConn.connect(function () {
                         done();
                     });
-                }, true)
+                })
             } else {
                 // Without force flag, we will refuse to cycle an active connection
                 done(new Error(RED._('mqtt.errors.invalid-action-alreadyconnected')));
@@ -760,14 +769,11 @@ module.exports = function(RED) {
                 }
             }
         };
-        node.disconnect = function (callback, force) {
-            const _callback = function (resetNodeConnectedState, _force) {
-                setStatusDisconnected(node, true);
-                if(resetNodeConnectedState || _force) {
-                    node.client.removeAllListeners();
-                    node.closing = true;
-                    node.connecting = false;
-                    node.connected = false;
+
+        node.disconnect = function (callback) {
+            const _callback = function () {
+                if(node.connected || node.connecting) {
+                    setStatusDisconnected(node, true);
                 }
                 if(node.client) { node._clientRemoveListeners(); }
                 node.connecting = false;
@@ -797,17 +803,18 @@ module.exports = function(RED) {
             };
             if(node.connected && node.closeMessage) {
                 node.publish(node.closeMessage, function (err) {
-                    node.client.end(endCallBack);
-                    _callback(true, force);
+                    waitEnd(node.client, 2000).then(() => {
+                        _callback();
+                    }).catch((e) => {
+                        _callback();
+                    })
                 });
-            } else if(node.connected) {
-                node.client.end(endCallBack);
-                _callback(true, force);
-            } else if(node.connecting) {
-                node.client.end();
-                _callback(true, true);
             } else {
-                _callback(false, force);
+                waitEnd(node.client, 2000).then(() => {
+                    _callback();
+                }).catch((e) => {
+                    _callback();
+                })
             }
         }
         node.subscriptionIds = {};
@@ -889,8 +896,18 @@ module.exports = function(RED) {
                     qos: msg.qos || 0,
                     retain: msg.retain || false
                 };
+                let topicOK = hasProperty(msg, "topic") && (typeof msg.topic === "string") && (isValidPublishTopic(msg.topic));
                 //https://github.com/mqttjs/MQTT.js/blob/master/README.md#mqttclientpublishtopic-message-options-callback
                 if(node.options.protocolVersion == 5) {
+                    const bsp = node.serverProperties || {};
+                    if (msg.userProperties && typeof msg.userProperties !== "object") {
+                        delete msg.userProperties;
+                    }
+                    if (hasProperty(msg, "topicAlias") && !isNaN(Number(msg.topicAlias))) {
+                        msg.topicAlias = parseInt(msg.topicAlias);
+                    } else {
+                        delete msg.topicAlias;
+                    }
                     options.properties = options.properties || {};
                     setStrProp(msg, options.properties, "responseTopic");
                     setBufferProp(msg, options.properties, "correlationData");
@@ -900,23 +917,36 @@ module.exports = function(RED) {
                     setIntProp(msg, options.properties, "topicAlias", 1, node.serverProperties.topicAliasMaximum || 0);
                     setBoolProp(msg, options.properties, "payloadFormatIndicator");
                     //FUTURE setIntProp(msg, options.properties, "subscriptionIdentifier", 1, 268435455);
-                    if (options.properties.topicAlias) {
-                        if (!node.topicAliases.hasOwnProperty(options.properties.topicAlias) && msg.topic == "") {
+
+                    //check & sanitise topic
+                    if (topicOK && options.properties.topicAlias) {
+                        let aliasValid = (bsp.topicAliasMaximum && bsp.topicAliasMaximum >= options.properties.topicAlias);
+                        if (!aliasValid) {
                             done("Invalid topicAlias");
                             return
                         }
                         if (node.topicAliases[options.properties.topicAlias] === msg.topic) {
-                            msg.topic = ""
+                            msg.topic = "";
                         } else {
-                            node.topicAliases[options.properties.topicAlias] = msg.topic
+                            node.topicAliases[options.properties.topicAlias] = msg.topic;
                         }
+                    } else if (!msg.topic && options.properties.responseTopic) {
+                        msg.topic = msg.responseTopic;
+                        topicOK = isValidPublishTopic(msg.topic);
+                        delete msg.responseTopic; //prevent responseTopic being resent?
                     }
                 }
 
-                node.client.publish(msg.topic, msg.payload, options, function(err) {
-                    done && done(err);
-                    return
-                });
+                if (topicOK) {
+                    node.client.publish(msg.topic, msg.payload, options, function(err) {
+                        done && done(err);
+                        return
+                    });
+                } else {
+                    const error = new Error(RED._("mqtt.errors.invalid-topic"));
+                    error.warn = true;
+                    done(error);
+                }
             }
         };
 
@@ -1130,6 +1160,7 @@ module.exports = function(RED) {
                         node.brokerConn.unsubscribe(node.topic,node.id, removed);
                     }
                     node.brokerConn.deregister(node, done);
+                    node.brokerConn = null;
                 } else {
                     done();
                 }
@@ -1194,6 +1225,7 @@ module.exports = function(RED) {
             node.on('close', function(done) {
                 if (node.brokerConn) {
                     node.brokerConn.deregister(node,done);
+                    node.brokerConn = null;
                 } else {
                     done();
                 }