http://xmpp.org/software/libraries.shtml lists some example php libraries.

I'm thinking a 1.2 plugin?

What exactly would this do?

Notify about change issue.

Paul, John write after release branch 1.2.x, he will be think about system integration, such jabber and other.

What we should do is build support for notifications. Notifications should be triggered based on actions in the system that the users would need to be notified about. There can be several plugins that handle such notifications including:

1. Email
2. Jabber
3. SMS
4. Twitter (e.g. via direct / broadcast messages as appropriate).

The email plugin should be built in (i.e. core plugin), and the others should be installable.

ping, what about this ticket?

Anybody here?....
jabber notifications are needed and actual theme.

for first time with text "changes was made in ticket", at least, to watchers...

Well, what would be needed to implement a Notification API as vboctor suggested?

I would suggest the following approach:

1. Add plugin events all on events that currently trigger emails.
2. Implements email notifications as a plugin. This enables alternative notification technologies as well as possible implementation of other email notifications (e.g. fancy html notifications).
3. Short message notifications (text messages, jabber, twitter and others). This includes providing information about their address and possibly going through a verification process. This is related to phone number for text messages, twitter handle, etc. Jabber and Twitter plugins can be a good start here.

+1 to vboctor's outlined approach.

https://github.com/mantisbt-plugins/jabber-notify