What he probably meant is: You don't want your mobile to be notified about presence unless you open the client and look at your roster. Or if you set a trigger to be notified if someones presence reaches a certain state. When you control the server side both is possible with XMPP. You could use privacy lists XEP-0016 for that. You'd just have to make sure that the server sends the last presence when you enable presence notification after you disabled it while the client was not in the foreground.
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What he probably meant is: You don't want your mobile to be notified about presence unless you open the client and look at your roster. Or if you set a trigger to be notified if someones presence reaches a certain state. When you control the server side both is possible with XMPP. You could use privacy lists XEP-0016 for that. You'd just have to make sure that the server sends the last presence when you enable presence notification after you disabled it while the client was not in the foreground.