SP 8.1 output smart material cannot be read in 7.3.4

[辰祠26287927447q]

The work needs to change the 8.1 file to 7.4.3,
But the way to convert smart materials to lower versions doesn't seem to work at the moment.

This has been the case for a long time to exchange data between different versions.

But currently it doesn't work....

Or is there a better way to convert?