Hello, can you elaborate? are you having problems with tool?

 If you have a DS708 with old software that works just fine, I would not risk doing some sort of available firmware update  and then doing the final updates to the vehicle make software. The DS708 used to be the Flagship scanner that Autel claimed to be at 90-95% of the Factory tool capability and do could do almost everything except cut cheese, but after Maxi Sys came out it somehow got dismissed as almost an entry level , oil bay scan tool with Minimal coding capability. I believe the later updates after 2014 may have Dumbed functionality down due to lawsuits and possibly to make the newer faster platforms seem more attractive as it was being phased out. Do you trust the free update for DS708?
  If you have a non functioning DS 708, by all means take advantage of your last chance to update to the final version software level and possibly get a brick working again, however if you have a perfectly working DS708 and just want to get an extra model year of coverage, and find out that the firmware update does something internally that prevents you from using your older software for old functionality, I wouldn't be surprised it even times out the tool.
 Unfortunately Support is not to be found on here to answer your question about what the firmware does, so you just have to assume it's something court and not in your best interest, and  give you a little bit newer car model coverage for some makes in exchange  for disabling certain court contested functions.
  Has anyone that has updated their old DS708 to current level (since the updates has been made free) , tried their old back up software SD cards and see if they can work on Ford ?

 I plugged the DS708 with the updated software into a 1998 ford explorer to try to read transmission codes since the overdrive light was on or flashing(don't recall clearly) but I don't know if the tool is or was capable of doing that, problem is, I couldn't access trany computer to read data or codes. I found some ABS codes and I believe a transmission reverse error code under the ECM. I did not try the saved SD card because the explorer owner did not come back after clearing those mentioned codes.

  A 98 Explorer has a PCM (Powertrain Control Module that also controls the  transmission besides the engine. I'm just curious if the old SD card with the older software still works fine or the final updating does something to the firmware that prevents the Maxidas from runningthe older software versions on saved SD cards similar to how the system upgrades on MaxiSys prevents you from running older backup software used with earlier system versions.

 Most likely updating to the newer versions won't prevent from running older saved versions. Today I was interchanging SD cards and everything looks the same, I tried it in a 2000 volvo v40 with both cards and to begin, volvo version (v9.0) is the same and I could not read IM readiness status, had to go to OBD II generic to verify this data.