Upgrade Project from Grails 1.X to 3.5.11

I have a Legacy app with Grails 1.X and Java 1.6, which needs to be upgraded to Grails 3.5.11 and Java 1.8. Code changes over the screen share is recommended. If not on screen share, then should be able to walk me through over the zoom call to explain what changes are needed and how to do it. If local environment setup is required to run the project on local, then should be able to help.