Boeing recently announced that starting in January 2022, Fidelity will become the new service provider for Boeing retirement benefits, including the Boeing 401K, SSP and Executive SSP nonqualified retirement plans. The pension plans will also transition in July 2022.
It appears there will be no action required on the part of Boeing employees. Per their announcement:
There were no details about whether this might affect the investment options going forward once the dust settles from the transition to Fidelity.
You can read their full announcement here.