I've opened a support request (https://support.zabbix.com/browse/ZBX-2572) about zapcat triggers and the 1.8.3 GUI. It looks like zapcat does not use supported trigger formats (although the server seems to work with existing ones as I have some dev systems working with it) so if you try to modify a trigger it won't work and throws an error. I've contacted kjkoester to see if he can help out. If there are any other developers working on zapcat, any help would be much appreciated (I don't know Java or I would give it a go).
-Dan
-Dan