Have you changed the donation address to yourself since you are the one working on it?

No, the donation address is still the one that belongs to pokkst. Considering that the only thing I've done is bumping monero version (with cherry-picking polyseed & coin-control patches) and some very minor changes - I think it wouldn't be fair to immediately change it :)

Or if not, have you decided where donations will go? Or if you will turn them off entirely?

At least for now, I think it is only fair that donations will still go to pokkst for all the work he has done.

However, if pokkst will not return to continue the development of mysu and I will be the actual new maintainer of the wallet (which means doing something more than just bumping versions here and there, e.g. adding new features), then I'll probably change the donation address to my own. In that case though, I'll probably also have to change the name of the wallet, because technically I don't have permission from pokkst to use "mysu" name. But this is a problem for another day (unless pokkst will reappear and explicitly say I can't use it - in this case I'll change it immediately).

Some context for people not familiar with mysu: the donations that we are talking about is an optional (and I think disabled by default) feature that adds 0.5%-3% donation to your transaction with 10% chance (so it would donate 0.05%-0.3% of your total "volume" using the wallet to the donation address).