Upgrade Asterisk - Unicall Involved

We have an implementation in Mexico that has voice channels coming in via E1. A consultant who is no longer available to us did the setup. None of our other installations in the US, Canada, or Brazil use Unicall.

We are experiencing a bug that causes extensions to perminantly go on hold until Asterisk is restarted. We are running Asterisk 1.4.9. It appears that this bug was fixed in a subsequent build. We have been warned that an upgrade of Asterisk could break Unicall, and don’t yet have the internal resources to rebuild Unicall quickly.

Two questions; first, does anyone have any experience with Unicall in Mexico who could give us the proper procedures to upgrade Asterisk without breaking Unicall?

Second, does anyone know a reliable resource in Mexico City that could provide support of Asterisk implementations?