Zabbix 6 regexp: incorrect expression "6\.0"

[Airler]

It seems that it doesn't work again in Zabbix 7.0

This regex is valid but not working

[B]^[A-Z]{3}AT[A-Z][0-9]\.D20[0-9]{5}\.T[0-9]{6}[/B]

I'm trying to double backslash the dot

I guess [ B] and [/B ] in your code snippet are not really part of your regex?!
Otherwise you should need to escape the /.