Please go to the download page and find NM.version atached.

Edit and copy it to run number subdirectory.

 

You can open and edit this file in editor program.

For NONMEM 7

"x"
"1" "NM7"

For NONMEM 6

"x"
"1" "NM6"

 

Regardless of what version of NONMEM you used, the nemae of this file should be "NM.version"

 

If you used NONMEM 6, you don't have to follow this process because fit4NM 3.3.8 is working well with NONMEM 6.