PCIe 5.0 M.2 SSD Slot

can someone help me with the new PCIe 5.0 standard that is supposed to appear at some point?
I read that the new PCIe 5.0 M.2 SSD connector should have a width of 25 mm. Is that correct?
M.2 SSD are backward compatible. A 4.0 M.2 SSD will work in a 3.0 connector. But vice versa?
Will a PCIe 4.0 SSD work on a 5.0 connector?

The answer can be found >here<.