Locking Zoho sheets

When two persons open a Zoho sheet and work on it at the same time, the latest version gets saved erasing the other persons work.

This could be resolved by having real-time updates as in google spreadsheets or by locking the spreadsheet in use when someone is working on it. I believe that the first option is preferable, that way more than one person can work on the same spreadsheet.

Thank you

Jairo Rodriguez