Comment by charlieboardman

From what I can ascertain, the new bigger battery is incompatible with the old chassis: https://frame.work/products/pro-battery-74wh

"This product can only be used with both the Framework Laptop 13 Pro Bottom Cover and Framework Laptop 13 Pro Input Cover."

I applaud that the mainboard and keyboard are backwards compatible, but I don't think the pro is quite as backwards compatible as some are thinking