I just came across the new Tantan FM122 frame, which seems to be an updated version of the FM121.
At first glance, it looks like they have redesigned the rocker link and kinematics. The top tube and the shock mounting area also appear to have been revised compared to the FM121.
The frame is listed as a 29er, Boost, UDH-compatible XC frame, using a 190 × 45 mm rear shock.
So far, it looks like only size M is available, but it could be interesting to see whether larger sizes will be released later.
Here is the link:
https://www.seraphbikes.com/chameleon-White-Seraph-Logo-29er-Boost-Suspension-Carbon-Mountain-Bike-Frame-FM122-UDH-Hanger-XC-Frame-Compatible-190x45mm-Rear-Shock-p7202729.htmlOne thing worth mentioning is that the FM121 was removed from the product lineup some time ago. I also came across reports of failures on some FM121 frames around the top-tube area. As far as I understand, there was some speculation that this could have been related to the frame design, construction, or possibly the suspension kinematics.
I don't know whether those reports were ever officially confirmed or what exactly caused the failures, so I don't want to jump to conclusions. However, considering how much the rocker, kinematics, top tube and shock mounting area appear to have been changed on the FM122, I wonder if these changes could be related to the issues with the previous FM121.
I'd be interested to hear if anyone has more information about the FM121 issues or knows what exactly has been changed in the FM122.