You can manually replace the comskip.exe file in the MCEBuddy 2.5.7 comskip directory/folder with your newer donator version of comskip you get from the comskip site without paying for the premium version of MCEBuddy, if that’s what you’re asking.
You can do the same for Handbrake and FFMPEG too. I’m not sure when the custom command line options for comskip came in, so that will use the newer version of comskip, but it won’t use command line options.
See my other thread on manually upgrading comskip, Handbrake, and FFMPEG if that’s what you’re trying to do (upgrade just comskip in 2.5.7 because you don’t have the premium MCEBuddy 2.6.x version).
However, it looks like the MCEBuddy premium 2.6.x version now has a custom compile of the latest comskip donator version (if I read Goose’s responses correctly), so you’ll only get that by paying for the premium MCEBuddy to get the 2.6.x versions.
I’m assuming the comskip in the current premium MCEBuddy 2.6.x was built from source and with a newer compiler to take advantage of optimizations and CPUs that weren’t available when the comskip donator was released, or to integrate with a newer embedded FFMPEG, since there’s been some changes with regards to AV1/VP9 since the comskip donator release.