Upgrading from 10.2.2 to 11

[Yasser]

Hello,

I'm working in a project using IBM Cognos 10.2.2, The project have many modules in a stable state and we use a lot of option and the client need a lot of the reports to be printed as pdf so we have many design customizations, I want to upgrade the system to Cognos Analytics but I'm not sure if everything will be the same in the old reports and dashboards, I depend on the basic report and pdf style sheets and I don't know if there are any change in them.

Is it 100% safe to upgrade ? and what is the requirements ?