Update Nextcloud

Firstly, I know that what I am asking is unsupported, I just want to know if anybody can point me in the right direction.

Today I got the below message in the ownCloud client:

I saw this post from a little while back and was going to reply there but thought it best to start a new thread.

I had been thinking about upgrading Nextcloud anyway. So, could anyone possibly point me in the right direction as to how one could upgrade Nextcloud to the latest or does anyone know if the next MiaB update will include the latest Nextcloud (and roughly when)?

Thank you.