Is Boeing planning a new single-aisle Jet to eventually replace 737 MAX?

Boeing is said to be in the early stages of developing a new single-aisle airplane that could eventually replace its 737 MAX, according to a report by the Wall Street Journal. Boeing and Rolls-Royce have not publicly commented on the news.
The 737 MAX, which entered service in 2017, was grounded worldwide in 2019 after two fatal crashes killed 346 people. The grounding caused huge losses for Boeing, along with lawsuits, investigations, and a criminal probe by the US Department of Justice. The Federal Aviation Administration (FAA) lifted the grounding in 2020, during the COVID-19 pandemic. Last week, the FAA said Boeing could start issuing airworthiness certificates for some 737 MAX jets, a permission that had been revoked after the crashes.
Earlier this year, Boeing CEO Kelly Ortberg reportedly met with Rolls-Royce officials in the UK to discuss a new engine for the upcoming aircraft. Boeing is also designing the flight deck for the new plane, though the project is still in the early planning phase and no final decisions have been made.
Boeing continues to face regulatory scrutiny. In early 2024, the FAA imposed a production cap of 38 737 MAX planes per month after a mid-air incident on an Alaska Airlines jet, where a cabin panel blew out due to missing bolts. This incident led the U.S. Justice Department to investigate Boeing for not complying with a 2021 deferred prosecution agreement, which had been put in place after the company misled the FAA during the 737 MAX certification process.
Despite these challenges, Boeing says its recovery plan is on track, with priorities including the delivery of around 6,000 backlogged airplanes and the certification of previously announced aircraft models.