Hello
Version 11.5.11.1470 is XI Release 2 SP 5.
So you can migrate your content from this version directly to the latest version of BI4.x (BI4.2 SP2 currently).
You simply run the Upgrade Management Tool, of BI4.2 SP2, and set the source as your XI release 2 SP5 machine.
You'll only have to use BIAR files if you're on a non-Windows machine for running Upgrade Management Tool.
Regards, Matthew