WinSCP does not support this.

Btw, would you want it to blindly append the tail of the file? Or would you want it to also check that the previous part is really the same?

The current synchronization is:

synchronize remote -delete -filemask="|*.lock" c:\folder /share/Profiles

Every time a file in the local folder is changed, it syncs it to the remote one.

Is it possible to synchronize like this, for example:
1. The local folder contains one file, eg 10GB.
2. The remote folder already contains this 10GB file.
After changing the file from the local folder from 10GB to 11GB, I would like the whole file not to be copied to the server, but only to add the missing 1GB to the file. Is there any way to do this?