Reply to Help Save the Tour with Serato Help!!!

Hi, I'm DJ Tittsworth's personal intern and while he's on Tour now ( http://www.tittsworth.com/calendar/ ) he has emailed me with an issue with Serato that we desperately need to fix. Apparently right after he upgraded to the 2.2 software, the software has been crashing on him mid-set during his gigs.

"well, i am on 2.2 now and that's the second city in a row where it
just went DEAD mid set. i had to reset the application. luckily i
dont freeze up as easily. i guess it coulda been a bad connection or
some shit but honestly, it's the first time it's ever happened and it
was RIGHT after i upgraded so that i could get a SL4 box to work.
what's the latest most stable version that works w/ SL4? are there
known issues on serato's community w/ 2.2 freezing? also i believe i was
using SL2 on 2.2 when it hapepned. thx my dude"

Is there any way he can still use the SL4 box with a previous version of the software? And if so, how would you go about doing so? I'm a Traktor person, so I'm not familiar with that software. If you can help out in any way it would be much appreciated, and might possibly save the tour!