why 0.96.0.1-testing but not just 0.96? I do not like the word testing.
0.96 has some weirdness that has been fixed for 0.96.1 but 0.96.1 is still in the testing phase.
And one more Q. Is it mandatory for me to migrate or I can continue to enjoy bitcoin with 0.93.3 ?
You can still use Bitcoin with 0.93.3. However you will be missing all of the improvements to the database, performance, coin selection, fee control, etc. that have been made since.
Does it mean that that DB in v > 0.93.3 is much smaller in size? 0.93.3 runs very smoothly for me but its DB is very huge/