'Transcribe' wouldn't be the normal usage here, which implies that you made an exact copy of the old copy, which isn't what you did if you changed standards.
You could say:
"I re-wrote the old version of the code with our new standards"
"I changed the old version of the code to use our new standards"
"I updated the old version of the code to use our new standards"
They key here, is that you want to signify that the old code wasn't only copied, but changed as well, which in the cases above are signified by changed, updated, or re-written.
Personally, I would use re-wrote or updated, which both imply that you're making the code more current, which is what you're doing by using new standards.