All other old demans like Avantid will begin unify starting 2003.12 with SCL 8.4.2. But 2003.12 is not stable, it crash on me many times, now I switched back to 2003.03.
Never trust any software released before christmas holidays.
i have tried running old license for scl 1.2 on scl 8.4 with the 2003.12 releases. no problem. however for 8.4.2, the answer is no. so i don't see any reason changing from 8.4 to 8.4.2