Can I revert back to my old theme after updating on Dawn?

Hi, please help a Newbie. My current Theme, Dawn, has an update available (from v5 to v8)

I’m concerned that if I upgrade, and if I lose any of the functionality, could I revert to v5? I have no coding experience and would be in big trouble if the whole site crashed!

TIA

Thanks for your very quick answer, I did as you suggested but (very) quickly reverted. I thought that the new theme would “Auto Populate”, i.e. copy over all features of my existing theme, just providing enhanced features such as quicker search etc, but it appeared to be a blank template, having to start again. I don’t have the confidence to start again from scratch.

(My site was written by a small company who effectively took my money and ran, abandoning me to my own devices so I have no real idea what I’m doing!). I may have to employ someone else to help me with this