@hek @Anticimex First install https://github.com/esp8266/arduino-esp8266fs-plugin and upload the crt file to the ESP8266 file system.
then issue these command from the folder in which MySensors is installed:
sed -i 's/WiFiClient/WiFiClientSecure/g' Arduino/libraries/MySensors/core/MyGatewayTransportEthernet.cpp
sed -i 's/WiFiClient/WiFiClientSecure/g' Arduino/libraries/MySensors/core/MyGatewayTransportMQTTClient.cpp
change your GatewayESP8266MQTTClient to this:
/**
* The MySensors Arduino library handles the wireless radio link and protocol
* between your home built sensors/actuators and HA controller of choice.
* The sensors forms a self healing radio network with optional repeaters. Each
* repeater and gateway builds a routing tables in EEPROM which keeps track of the
* network topology allowing messages to be routed to nodes.
*
* Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
* Copyright (C) 2013-2015 Sensnology AB
* Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
*
* Documentation: http://www.mysensors.org
* Support Forum: http://forum.mysensors.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
*******************************
*
* REVISION HISTORY
* Version 1.0 - Henrik Ekblad
*
* DESCRIPTION
* The ESP8266 MQTT gateway sends radio network (or locally attached sensors) data to your MQTT broker.
* The node also listens to MY_MQTT_TOPIC_PREFIX and sends out those messages to the radio network
*
* LED purposes:
* - To use the feature, uncomment WITH_LEDS_BLINKING in MyConfig.h
* - RX (green) - blink fast on radio message recieved. In inclusion mode will blink fast only on presentation recieved
* - TX (yellow) - blink fast on radio message transmitted. In inclusion mode will blink slowly
* - ERR (red) - fast blink on error during transmission error or recieve crc error
*
* See http://www.mysensors.org/build/esp8266_gateway for wiring instructions.
* nRF24L01+ ESP8266
* VCC VCC
* CE GPIO4
* CSN/CS GPIO15
* SCK GPIO14
* MISO GPIO12
* MOSI GPIO13
*
* Not all ESP8266 modules have all pins available on their external interface.
* This code has been tested on an ESP-12 module.
* The ESP8266 requires a certain pin configuration to download code, and another one to run code:
* - Connect REST (reset) via 10K pullup resistor to VCC, and via switch to GND ('reset switch')
* - Connect GPIO15 via 10K pulldown resistor to GND
* - Connect CH_PD via 10K resistor to VCC
* - Connect GPIO2 via 10K resistor to VCC
* - Connect GPIO0 via 10K resistor to VCC, and via switch to GND ('bootload switch')
*
* Inclusion mode button:
* - Connect GPIO5 via switch to GND ('inclusion switch')
*
* Hardware SHA204 signing is currently not supported!
*
* Make sure to fill in your ssid and WiFi password below for ssid & pass.
*/
#include "FS.h"
#include <EEPROM.h>
#include <SPI.h>
// Enable debug prints to serial monitor
#define MY_DEBUG
// Use a bit lower baudrate for serial prints on ESP8266 than default in MyConfig.h
#define MY_BAUD_RATE 9600
// Enables and select radio type (if attached)
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69
#define MY_GATEWAY_MQTT_CLIENT
#define MY_GATEWAY_ESP8266
// Set this nodes subscripe and publish topic prefix
#define MY_MQTT_PUBLISH_TOPIC_PREFIX "mygateway1-out"
#define MY_MQTT_SUBSCRIBE_TOPIC_PREFIX "mygateway1-in"
// Set MQTT client id
#define MY_MQTT_CLIENT_ID "mysensors-1"
// Enable these if your MQTT broker requires usenrame/password
#define MY_MQTT_USER "admin" //your MQTT username
#define MY_MQTT_PASSWORD "admin" //your MQTT password
// Set WIFI SSID and password
#define MY_ESP8266_SSID "yourwifissid"
#define MY_ESP8266_PASSWORD "yourwifipassword"
// Enable MY_IP_ADDRESS here if you want a static ip address (no DHCP)
#define MY_IP_ADDRESS 172,16,0,120
// If using static ip you need to define Gateway and Subnet address as well
#define MY_IP_GATEWAY_ADDRESS 172,16,0,1
#define MY_IP_SUBNET_ADDRESS 255,255,255,0
// MQTT broker ip address.
#define MY_CONTROLLER_IP_ADDRESS 172, 16, 0, 95
// The MQTT broker port to to open
#define MY_PORT 8883 // note this change its port 8883 as per standard for SSL over MQTT
/*
// Flash leds on rx/tx/err
#define MY_LEDS_BLINKING_FEATURE
// Set blinking period
#define MY_DEFAULT_LED_BLINK_PERIOD 300
// Enable inclusion mode
#define MY_INCLUSION_MODE_FEATURE
// Enable Inclusion mode button on gateway
#define MY_INCLUSION_BUTTON_FEATURE
// Set inclusion mode duration (in seconds)
#define MY_INCLUSION_MODE_DURATION 60
// Digital pin used for inclusion mode button
#define MY_INCLUSION_MODE_BUTTON_PIN 3
#define MY_DEFAULT_ERR_LED_PIN 16 // Error led pin
#define MY_DEFAULT_RX_LED_PIN 16 // Receive led pin
#define MY_DEFAULT_TX_LED_PIN 16 // the PCB, on board LED
*/
#include <ESP8266WiFi.h>
#include <MySensor.h>
void setup() {
if (!SPIFFS.begin()) {
Serial.println("Failed to mount file system");
return;
}
File ca = SPIFFS.open("/ca.crt", "r"); //replace ca.crt with the ca file name
if (!ca) {
Serial.println("Failed to open ca file");
}
else
Serial.println("Successfully opened ca file");
if(_ethClient.loadCertificate(ca)) //_ethClient as defined in MyGatewayTransportMQTTClient.cpp
Serial.println("loaded");
else
Serial.println("not loaded");
}
void presentation() {
// Present locally attached sensors here
}
void loop() {
// Send locally attech sensors data here
}
NB: i used https://github.com/owntracks/tools/raw/master/TLS/generate-CA.sh for generating the ca files
will post in Development...... 
