Repeat steps two to 4 for all of your outdated BRK alarms. We propose changing all alarms while in the process jointly to keep up optimum procedure operation; failing to take action may possibly compromise interlink overall performance. 02 would require to get up to date by thirtieth September 2021 https://www.firesense.co.uk/type/addressable-fire-system/addressable-fire-alarm-control-panels/