How to avoid session timeout in Iphone6,Iphone7(IOS 11.2.6) for Moodle mobile app…?

by Arshad Syed.  

Moodle mobile 3.3.2 is getting logged-out after 4 hrs. It's inactivity on iPhone 6, iPhone 7 (IOS 11.2.6), but its working fine (It's not logging me out even after 24 hrs of inactivity) on Android devices and iPhoneX(IOS 11.2.6).

I did some changes to moodle code site like :

in config.php :

$CFG->sessiontimeout = 31557600;

and also changed in the database mdl_config as

session timeout : 31557600

But still, it's not working... Any Suggestions to solve this issue?