I do have 2.3.34 test version. Function is located under IPC module, below is the download link.
http://forscan.org/download/FORScanSetup2.3.34.test20200521.exe
Important notes:
1. Please note this function can increase mileage, not decrease it. So if you enter wrong number that is bigger than have to be, you will not be able to return it back. So please be very careful.
2. Before run the change, please make sure FORScan show correct *current* mileage (it shows it when asks to enter new mileage).