he messaged me out of the blue, we broke up

long story short. I dated this guy for about six months, he broke up with me because he got a job in another city and was also moving to same city as where his ex lives.. even though they not together.

I didn't remain in touch with him after the break up. the other day he message me with a new number and ask how I am and if I wanted to catch up?!

it must be it didn't work out with his ex?

what do you ladies suggest I should ask him and respond?