saguaros 
OK, so if you update from 5.4.1 to J6 you have to disable this plugin, as above you are saying you need this for your templates to work - so if we disable and then update - my concern is that the admin area again is messed up and then we cannot re-enable that plugin, or can you assure me that if we update per above we can still access plugins?
I don't want to do this and find out its broken and waste more time fixing that?
Look forward to hearing from you,
Mark