Hi Chris,
there are two ways to update to B2B. You can't do it via a Web upgrade from the menu.
B2B needs a later version of the Linux operating system so can't be simply upgraded in situ.
1. Download the software and create a new bootable SD card as described here
You will need a new blank SD card, ,an SD card reader/writer and of course a computer as above.
2. Order a new SD card loaded with the B2B software from Brennan
The best thing is to email thebrennanb2 @ gmail . com - no spaces.
Tell them what model of B2 you have, when you purchased it and where you are in the world.
Also whether you have B2 with the larger side mounted SD card or the micro SD card which sits inside the B2 case.
Paul from Brennan will pick up your email and/or pick up your need from this thread.
Make sure you say you want the card loaded with the B2B software though that may now be the default.
John