X3c is free to X3 users. Certainly, it fixes some issues still open/unresolved in X3b. We've begged and pleaded with Cakewalk to release updates more often than before, so a post like this is counter-productive here. To the OP, and with all due respect, if you will upgrade to X3c, and then report issues you're having or find, then it benefits everyone, including yourself. If you're having a problem in X3b, and expect it to be fixed in X3d, unless you confirm it to still be a problem in X3c, then it's likely not going to be high on the punch list for X3d.
Lastly, are you actually having issues with X3b? Or are you expecting you will?
Please upgrade. You'll be fine.
