https://defence-blog.com/news/u-s-air-force-awards-contract-to-boeing-for-integrating-new-lrso-cruise-missile-on-b-52h-bomber.html
The LRSO weapon system constitutes the cruise missile, pylon, rotary launcher, software and aircraft using MIL Standard 1 760 as the interface. The ceiling value is $250M utilizing Research, Development, Test and Evaluation (RDT&E) FY 2019 – FY 2023 funds.
Boeing, as the original aircraft manufacturer, is the only source with the unique experience, expertise, and facilities to satisfy specific LRSO B-52 weapon system integration requirements. Boeing designed, developed, and produced the B-52 and has maintained the design since the 1950s.
The B-52 cannot penetrate adversary air defenses; therefore, without the LRSO, the B-52 will cease to play a role in the nuclear mission once the AGM-86 is retired, and the retirement of this weapon might occur before the B-21 is operational in the nuclear role in significant numbers.
If the AGM 86 nuclear cruise missile becomes obsolete well in advance of retirement, then the B-52 could become irrelevant in the nuclear role by the late 2020s.