Regime selection for Belated return

I am an individual having business income filed my return under new tax for previous year now for current year i am filing belated return, now the question is in which regime i should file my return

1. Under old scheme or New scheme

If i proceed with Old scheme, which tax rate would be applicable for me in next year, is it new or old.

For new rate i have read some articles where they are stating we cant go by new tax rate for belated return.

I am confused by which rate i should go or income tax allow me to file.