I'm fairly certain that is a OS10 only switch.  Is there something you need with stacking that VLT will not work for?
Hi I have acquired 2 PowerSwitch S5248F to implement stack But they come with the OS10,  I understand this version does not support Stacking. Is it possible to downgrade the OS10 to the OS9 version? And if possible, is there an official Dell guide to do so? Thanks Martin    
Downgrade from OS10 to OS9 on a PowerSwitch S5248F-ON