The best use I can think of for my dormant S2 is to use the power supply for a S5 or S7.
Honestly I would sell it whal it still has value. Either buy btc or a new miner.
The longer you wait for upgrade kit the lower the miner will be worth. So good deal... not really. But this has been quiet so long I would go selling route vs waiting and hoping for something that might not come.