My students need to type in Burmese and they've pointed out that Firefox 4 doesn't handle Burmese input properly in many cases. Is it possible to lock to version 3.x without locking to a specific 3.x version? I want to be sure the machines don't auto-update to FF 4.x but I also don't want to block any security fixes, etc. that might potentially be released for FF 3.x