Yup ! due date for an unaudited proprietary concern is31st July. And as CA Saurabh Shukla say, it should be filed before due date in case of loss to avail benefits.
ya due date for non audit cases is 31st July and if there is any loss in the current year the return has to be filed within the due date u/s. 139(1) to avail the carry forward benefits .