I should have said that I have tried the uppercase variant - that does not matter.

I guess the weird spelling of "StatuS" is the author's way of telling you that it's case-insensitive.

I finally figured out what I need, even though I don't totally understand it (that I know hardly anything about the jabber protocol probably does not help).

This seems to work:

$con->PresenceSend(type => "unavailable");
[download]

However this does not:

$con->PresenceSend(type => "available");
[download]

But this does:

$con->PresenceSend(to => 'mh@mh.com');
[download]

Now my pi-client is green and available on my phone. I can only assume that in the jabber protocol you advertise your availability to certain jids, so leaving "to" out was the problem....

Strangely enough this does not work either:

$con->PresenceSend(type => "available", to => 'mh@mh.com');
[download]

But now I can't be bothered anymore.

I wonder if AnyEvent::XMPP would be a better libary....