With a new broadband package I'm been switched over to fibre.
I have a number of burglar alarms in my house, what do I need to do or will the alarms become obsolete, if so from what date will they become obsolete? I've tried to get through to BT via email but they have it well hidden
You need to talk to your alarm company, not BT.
If you are moving to full fibre to the home, you will almost certainly be moved to Digital Voice (VoIP). Depending on how your alarms are connected it may be possible to utilise either the Analogue phone port at the rear of the supplied hub or DV adaptor.