The notification says
The last date for making declarations under the Income Declaration Scheme 2016 is 30th September, 2016 which coincides with the last date of filing Income-tax returns by the tax payers whose accounts are audited and who are required to furnish the returns of income for Assessment Year 2016-17 by 30th September, 2016 as per provisions of section 139 (1) of Income tax Act, 1961.
In order to remove inconvenience and to facilitate ease of compliance, the Central Board of Direct Taxes, in exercise of powers conferred under section 119 of the Income tax Act, 1961, hereby extends the ‘due-date’ for furnishing such returns of Income from 30th September, 2016 to 17th October, 2016, in case of tax payers throughout India, who are liable to furnish their Income-tax return by the said ‘due-date’.
CBDT also has clarified through a separate notification that the due date for Audit under section 44AB is also increased to 17th of October 2016. Notification link