Some time ago I started investigation for a better differential update algorithm. The first attempt was known as time-travelling tdmupdate (also "tdmsync"). The second attempt has been much more cumbersome, but I think it has reached some usable state.
Here is the new tdm_installer:
Windows (32-bit)
Linux 64-bit
Linux 32-bit
Note that it is not a finished application yet: it has some important features missing, probably bugs also.
If your TDM inst