Hi,
The "serial history" is in the HikaSerial TODO list. The history would store status modification, order/user assignation, etc.
When you want to delete a serial, there is a confirmation request, exactly like HikaShop order listing.
It is not possible to undelete an order but there is a "cancel" order status.
If we want to add a trash into HikaSerial, the best way is to create a new "deleted" status for serials but it would require some modifications in the HikaSerial core.
For the moment the delete function is quite "hard" because you can delete a serial which is attached to an order (you should click on "refresh association" in the order to get new serials).
With a special "deleted" status, HikaSerial should detect deleted serials and not count them for the associations. After that, if you undelete the serial, the order could have too much serials assign.
I have to think more about it, but it is now in the TODO list.
Regards,