Be careful. Zoho could perform a Google style rug-pull on you. Always scout for other options in that scenario. Personally I enjoy Purelymail[0]
I also, back up any important emails. The rest, I can lose and not cry.
Edit: Purelymail might be interesting if they had calendar syncing. Maybe when they've grown a bit more.
Zoho has done so, with the removal of POP/IMAP for their free tier without any notice.