My original Uniti came with the original 24/96 streaming board.
Shortly after, the streaming board on Unitis being shipped was upgraded to 24/192 version.
Mine got upgraded, so that can definitely be done.
Depends when the Uniti you are looking at was built whether you need / want this.
But has the internal DAC changed between the Uniti 1 and the current version?
Im not sure.
You could always send an e mail to Naim Support to ask what upgrade options they are able to offer based on current standard Uniti.
I guess you would need to be specific what it is you are looking for.