I am in the preparation Process of Upgrading from LTS2015 to 2016.I have below Questions It would be great if somebosy can advice on this.

As per Installation Instructions ,I need to do back up of Data and File system?? 1.If i am pointing to Same DB we don't need to Database Back Up right?? 2.What is the file System Backup means??

When I am upgrading to the Nuxeo 2016 From 2015 .I have currently is nuxeo-server-7.10-tomcat-sdk.zip .So i need to install nuxeo-server-8.10-tomcat-sdk.zip right??

Once I install this 1.I have do get Upgrading Your Nuxeo Packages that means for New Nuxeo Version (8.10 ) 2.Update the Nuxeo Studio Project.as Stated below

For Nuxeo Studio Upgrade,I just need to change the version Information In Application Definition        section studio right??I don't need to do any other things as far as studio upgrade??  

3.Upgrade Custom Code.So that means Our Project COde any that we modified Apart from Studio Code.Studio Customizations happen automatically right??