Why? HA can operate entirely offline without access to the internet. You aren't suppose to expose it to the internet, you can't but they advise against it.
In that configuration you only need to update the software when it no longer meets your needs. If it's working then there's no need to update it.
In that configuration you only need to update the software when it no longer meets your needs. If it's working then there's no need to update it.