Don't know if some of this info had been shared previously, but Zach at TPG has just posted some intel about the 787 retrofits...
https://thepointsguy.com/news/united...aris-retrofit/
Highlights:
- 788 to go from J36 to J28 and add W21; they'll primarily be used on leisure flights (whether that actually plays out remains to be seen).
- 789 to maintain J48 and add W21.
- First 788 expected to be done in December 2019.
- First 789 expected to be done in "early 2020".