FWIW. Although 'I' know that many people have been using the [COLOR= #0000ff]Ui2[/COLOR] shorthand to refer to the Ultegra Di2 drivetrain, the shorthand is probably fraught with future hazards ...
What will the inevitable 105 variant be referred to?
[COLOR= #0000ff]1i2 [/COLOR]== one 'I' two
[COLOR= #0000ff]Oi2[/COLOR] ([COLOR= #808080]that's a capital 'o'[/COLOR]) == O([COLOR= #808080]h[/COLOR]) 'i' two
[COLOR= #0000ff]something else!?![/COLOR]
[COLOR= #000000]or, simply use Shimano's probable 105 Di2 designation[/COLOR]
BTW. I have to believe that Di2 ([COLOR= #0000ff]D[/COLOR][COLOR= #66ccff]igital [/COLOR][COLOR= #0000ff]I[/COLOR][COLOR= #66ccff]ntegrated [/COLOR][COLOR= #0000ff]I[/COLOR][COLOR= #66ccff]ntelligence[/COLOR]), like STI, probably sounds better before it is translated into English OR it is supposed to infer some sort of Borg-like synthesis between the rider and the drivetrain which is manifested in the speed & precision of the chain transfer OR it is possibly supposed to infer some sort of AI is incorporated.