How to appear online on facebook through Android phone?

[Ashank]

I have both the official Facebook app and the Facebook Messenger, but on web it shows Mobile Icon and on other android phones it shows me as offline. There is no green dot. But my brother too has an android phone, and he is visible (i.e. green dot is present beside his name).
Why am I not visible online?
Android Version is same for both i.e. 2.3.6 and so is the app version.

[Siddu]

It actually depends on the android version you are using and the app version.