Due date of AGM is dependant on the date of closing of a Financial Year and not Balance Sheet signing date.
As per Companies Act 2013,
1. Due date of first AGM (i.e. for newly incorporated company) shall be 9 months from the date of closing of first Financial Year.
2. Due date of second and subsequent AGM shall be earlier of the following:
(a) 6 months from the date of closing of Financial Year, or
(b) 15 months from the date of last AGM.
Assuming from your Balance Sheet sigining date of 31.07.16 that the relevant Financial Year is 2015-16, FY closing date is 31.03.2016 and the Due date for AGM shall be earlier of the following dates:
(a) 6 months from the date of closing of Financial Year i.e. 30.09.2016, or
(b) 15 months from the date of last AGM.