Is this coin still CPU? Can it be CPU solo mined or now someone needs a pool?
have you read this thread here?
Yes, you can still mine this coin with CPU and of course you can try to mine it solo with CPU only.
But you will need extreme luck at diff 21 and >700MHs network rate to find a block within 1 year.
We're at 22 diff now and my pool is reporting a trajectory to 28. Soon even our largest miners will not be able to solo mine. CPU mining is also looking impracticable, which is good by me since it saves us from botnets.