Sorry right now we only provide one option for our customers. 
Later we will take such requestes into our worksheet and think out a way to solve this problem. 

BTW, do a backup for your card is pretty easy. Just copy all files in your card to your computer or another card.  

 once your Active Software Period expires, do you have to update or you may continue to use the tool without updates?

 You can continue to use the tool as is , but while you were still within your update period , you should have made a copy and paste of the original 4GB software card contents to your PC  (preferably while tool is brand new before even registering and updating)and then copy and paste to a new 16GB Sandisk class 4 card, then register the device and update it with the new larger 16GB card and save the original 4GB card it came with as back up software.
  To lessen chance of DS708 SD card corruption Never just unplug the tool from the car while tablet is  powered up , take a few seconds and click home icon and select power off and select yes. Avoid using the DS708 on any vehicle with a weak  run down battery where attempting to start the vehicle causes loss of power and communication with DS708.
  Presently a DS 708 can be bought new on line for only  $800 , so buying a new update for old DS708 for $500-$600 does not make sense to me if  you can get a completely new  DS708 with warranty   for spending an extra $200-$300 more. If the newer updates have compromised  functionality of  older car software due to on going  litigation , you still have the less compromised  older working DS708 to fall back on. If it turns out to be  false , that the newer updates compromised functionality for older cars, comparing the old and the newer on the same car , then sell the older DS 708  for $400-$500 and you basically only paid $400 to update and have a new DS7089(Albiet old model).
   With that cheap of price for a slower DS708, Until I hear that Maxi Sys Scan file backups made on a micro SD cards do  actually work to restore software on a Maxi Sys  after the free update period is expired and the question about a user  replacement lith ion  battery  made available for Maxi Sys platforms , I'm not as inclined to drop an extra $ just to  get a 20 second faster boot up time, an extra 1/2" screen ,  Andoid  , and an internal battery that  I can't get a replacement for in a few years.

    I don't believe Autel's legal woes are yet behind them . For the last 2 years a lot of the software has had to go through a lot of changes to determine if certain  functions are  legal for them to still retain any longer unless  a different style approach and work around can be created to make a function in contention work or they have be removed or at least shown to no longer work in a court of law if a work around is not hashed out in time by the court ordered compliance dates. Once those dates are set, it is illegal for Autel to retain, support, or supply older versions of software that may  no longer be considered legal to distribute any longer.
  That's what I think is the reason why they can't give you copy of older software  to you , and why you have to back up your old software versions when you can before you are out of update period. You could argue that it is still the same software versions now that it was last year on the majority of the makes, but they are not going to make exceptions and cherry pick the old from the new versions of each make .

 Where you can buy a DS 708 for$ 800 if he is taken out of production and officially dealer not sell it?

 Good luck on using your tool after your subscription expires..