Overlay config files not getting updated

I am working on OpenWrt 15.05.1 "Chaos Calmer" and I am new to openwrt. When any configuration file present under /etc/config are modified, the files that are under /overlay/upper/etc/config are not getting updated. I read somewhere that any change done in any of the files, will show up in the /overlay partition. But, it seems to differ in my case. I would like to understand what pointers I should look into to resolve this issue.

Any reason why you use such an old version? I don't think there's any support for it anymore.
But someone might still be able to answer your question.


That doesn't sound reasonable, so what do you want to achieve?
You should not access config files directly, instead use UCI API with CLI/ubus.