upgrade log4j to 2.x in grails 2.4.4

Question

i have upgraded my GGTS to 3.6.3, java to 1.8 and grails to 2.4.4. I need to update log4j to 2.x or better. is there a guide somewhere that will tell me what i need to do? Just plugging the dependencies into my buildconfig.groovy doesn't work as it leave the old log4j versions in the buildpath - i'm assuming these are default grails dependencies.

If someone has a guide or something that they could point me to that would be greatly appreciated.

updating buildconfig.groovy with new dependencies - doesn't work