MQTT migration issues

Im lost… i have tried lots of options from the other post, but i cant work out how to fix my mqtt since upgrading to the latest HA.

This is how i have my config set and working prior to the upgrade.

mqtt:
  binary_sensor:
    - state_topic: "home-assistant/window/contact"
  cover:
    - command_topic: "home-assistant/cover/set"
  light:
    - command_topic: "office/rgb1/light/switch"
  switch:
    - command_topic: "home/bedroom/switch1/set"

switch:
    - platform: mqtt
      name: "Fireplace"
      command_topic: "cmnd/fire_place/power"
      state_topic: "stat/fire_place/POWER"
      qos: 1
      payload_on: "ON"
      payload_off: "OFF"
      retain: false
      optimistic: false

Any help would be greatly appreciated.

There were no changes to the mqtt integration in the latest release.

What errors do you see in your system and supervisor logs?

Is the MQTT broker running?

Are messages being received at the MQTT broker (use MQTT explorer to check).