How to unlock top speed on newest/latest Ultra Cush (Gen 4)?

I just got my Ultra Cush yesterday and just got it assembled. I attempted to unlock the 28mph mode, but the P-settings have changed and it looks like that is not an option any longer. I saw a post where someone said you can cut a white wire under the seat, but I dont have any white wires??

Any suggestions or am I stuck at 20mph?