What you read is nonsense. There is something called the "Changed Product Rule" or CPR. It short, it says that any system you change when doing a new ATC has to step up to the latest version of the regulations.
No it read like Boeing had to do some serious changes to the gear but wanted to keep the type and were sounding out the FAA on whether they were going to be allowed. This isn't the article but hints to the problems:
The news that Boeing is considering a further stretch of its largest 737 MAX variant reflects not only the seriousness of the threat posed by the better-selling Airbus A321neo but also the company’s belief in the growth potential of its seemingly ever-flexible 737 design.
Though Boeing is not commenting on the concept, reportedly dubbed the 737-10, there is little doubt the move is a response to the A321neo’s growing sales lead and to pressure from loyal customers to do something about it. Most recent numbers indicate Airbus now has more than 4,515 orders for the A320neo family, of which 1,117 are for the A321neo. Boeing, which lists orders for 3,090 MAXs on its website, does not detail the breakdown of variants, but is believed to have accrued less than 500 orders for the competing 737-9.
Impetus for the initiative has grown since 2015, when long-standing Boeing customers such as Korean Air were driven to split purchases to include both MAXs and A321neos. Korean ordered as many as 50 A321neos, along with 737-8s and 777-300ERs, in a $12 billion deal announced at last year’s Paris Air Show. American Airlines—which launched the MAX with its order for 100 737-8s—also selected the
A321neo, as did Lion Air with orders for both. All Nippon Airways, which bought the A321neo over the MAX, is another single-aisle defection to Airbus.
To make the stretch worthwhile, Boeing will need to develop the variant quickly, possibly with as little as four years from launch to service entry. Although engine development is generally the pacing item, Boeing can take advantage of the more powerful Leap-1A variant of CFM’s Leap-1 engine series, already certificated and in production for the A320neo family. The use of the Leap-1A engine, rated at over 32,000 lb. thrust for the A320neo family, would provide more than 3,000 lb. additional thrust per engine over the Leap-1B, additional margin for higher weight takeoffs and longer range. ut because there’s no such thing as a free lunch, Boeing must confront the design challenge of how to install the larger Leap-1A on a wing designed for the MAX aircraft’s standard Leap-1B engine. The Leap-1A has a 78-in.-dia. fan and a maximum nacelle height of 93 in. while the -1B, with a maximum thrust rating at takeoff of just over 29,000 lb, has a 69-in.-dia. fan and a nacelle just under 89 in. in height at its deepest point. The basic -1A also weighs considerably more than its smaller sibling, tipping the scales at almost 7,000 lb.; the -1B weighs about 6,130 lb.
Boeing managed to get the Leap-1B under the wing of the MAX by extending the nose leg 8 in., and cantilevering the engine forward and upward of the wing leading edge. The company faces a bigger challenge with the Leap-1A, particularly if it wants to keep development costs under control by avoiding major surgery around the main landing gear bay. The focus of engineering studies will almost certainly be on options to extend the main gear by a similar amount without changing the pivot point of the leg. The alternate option of a wing box redesign would entail significant investment and resources, at a time when Boeing is already heavily committed to other developments such as the remaining MAX family members, the 787-10 and 777X.
While Boeing remains silent about the concept, Airbus has been quick to discredit it. Airbus A320 program chief Klaus Roewe says “the other guys are under tremendous pressure.” Speaking at an Airbus event in Hamburg, Roewe added that Boeing has “to do much more than just the engine.” A decision to go for the Leap-1A would have “huge repercussions for the airframe,” he says, and “there is no easy way out of the corner.”
Not surprisingly, John Leahy, Airbus chief operating officer-customers, was equally disparaging about the potential 737 stretch. “They will try to get close to a ‘me-too’ aircraft, but not quite get there. Boeing has not named the aircraft yet, but we have: We call it the Mad Max.” According to Airbus, the A320neo family has a market share of 59%. Leahy thinks the market split will stay at around 60/40 in Airbus’s favor. The A321neo has a market share of 79%, Airbus claims, far outselling the 737-9. Airbus has no plans to stretch the A321, he says. In his view, 240-250 seats is the upper limit for a narrowbody aircraft because of the need for reasonable turnaround times on the ground.
Airbus also says the adoption of the -1A engine will result in a “full loss of commonality” within the MAX family, although Boeing reportedly considers that a nonissue, particularly with some carriers already adopting both engine variants as part of mixed MAX/Neo fleets.
To at least one potential customer, leasing company AerCap, the issue is not so much lack of commonality but rather the potential strategic knock-on effect on Boeing’s amorphous New Midsize Airplane (NMA). AeroCap CEO Aengus Kelly says about the potential stretch, “Boeing will sell it. It will be fine. There is a big user base. The core of the market is the -8, but the -10 will bring the MAX family closer to the A320neo.”
However, he adds, “The new midsize aircraft is the real challenge. Is there room for another aircraft? In part, it depends on the [737]-10. There are a lot of discussions around that. To an extent, the -10 would take part of the NMA market.”
Aside from some of the structure, there is very little on the 737 Max that's not certified to 21st century regulations.
Yeah everything except the cockpit!