If I buy some cyberware or bioware at a rating less than the maximum (eg Orthoskin Rating 1) can I later upgrade it to a higher rating for the extra essence and cost? Or do I have to replace it all together and if so does this mean I lose the essence from the first piece of ware? Or is it not even possible at all?

The standard intepretation is that if you pull out a piece of cyberware or bioware, it leaves an essence "hole" that you can put other stuff in. So if you have a piece of ware that costs you 0.75 essence, and you want to put something in that costs a whole 1 point of essence, you can take out the first piece and put in the next and it will only cost you an additional 0.25 essence.

Upgrading current ware so that you don't have to pay the full cost is not suggested in the RAW however, and would be a kindness from the GM. You might be able to persuage a nice GM to let you do it, don't rely on that though. I think it would depend on what the ware was. Muscle augmentation? Might just be sticking some more fibres in there, pay the difference. Wired reflexes? Nah - all new kit, I'm afraid. Pay the lot.

HTH,

-K.

Depends on the GM.
Check with them first.

I would allow upgrades for most warez, as long as it was the same grade. I also charge a hefty price for the surgery, depending on if it is a new installation, upgrade or replacement.

I don't know why, but now I've got this funny image of trying to explain my intentions to another character.

"What are you doing this weekend, Nasser?"
"Well you remember last year when I had all my skin surgically removed and a plastic-based fibre weave grafted on to my flesh in its place?"
"Yeah,"
"Well I felt like doing it again."