when will we get oreo update for A5 2017..many countries have got oreo update. but we not..

brothers i want to know that samsung s7 gives APPLOCK features on their oreo versions???

In my A5 2017, i have downgrade my Android version from 7.0 to 6.0.1 but SecureFolder is not opening it shows (unauthorised software is installed) and SamsungMember's is also not opening.please Tell me what is the solution. {THIS IS MY SECOND DEVICE}...