If after than you are to late and won't be able to convert your coins. Exchange to the new blockchain took place between 20th and 23rd of november.
So, I can forget about all my coins?
I'm afraid so. You had a full month to do it. Announcement on how to convert was pretty clear I must say.
Nevertheless I'm sorry for your lose of coins. Might wanna think of rebuying as the dev has some nice thing going.
Cheers
Easily said, there are over 100 coins out there, not sure how we're expected to know when to check for a complete change in a coin rendering all previous coins worthless. Its not practical to check every thread on every coin, constantly.