Probably, Yoroï will after the hardfork be offline for a few days or even longer.
However, in order not to miss out on any rewards, you must have chosen a pool to delegate to, before the 2nd epoch starts, which is 5 days after the HF.
Therefore, it might be a good idea to install Daedalus and use your recovery-phrase from Yoroï and restore your Yoroï wallet there.
This will enable you to delegate your funds!
Once everything’s back to normal, your Yoroï wallet will function again as it always has, and you can uninstall Daedalus without a problem. 🙂