Update on United's domestic first class seats

"Can you write an article on why United uses tired old first class seats on their new 737s? What happened to that new seat that was rolling out more than a year ago? You wrote about it," texted long time reader PM, from a United flight to Houston from LAX.

So where is United with the standardization of domestic first class-- which is currently flying with at least three versions of seats that I'm aware of? Let's take a look.