They are all different from the original Opium. If you want the original, than get the original
I believe it was 4 or 5 years ago, the summer version was called "Fraicheur d'Orient" and came in a frosted bottle. This was alcohol free. It was lovely (a friend of mine owned it), and dries down into a subtle skin scent.
The year after that was a version I did not like, Opium d'Ete was the name if I'm not mistaken, which smelled to me just like the EDT but with the addition of melon note. It just smelled distasteful - like melon that fell into the ground and got covered with mud.
Than came Fleur de Shanghai (two years ago), which is my favourite of all - a softer though very Opium-y, with the addition of magnolia, and with more vanilla. To me this was perfection and I was sad to see that it would remain only a limited edition...
Last year, Fleur Imperiale debuted and it was similar to Shanghai, but not perfect. It was suppose to be surrounding the osmanthus and peach blossom theme. I just wasn't impressed. I have a bottle up for swap or sale of that. I got it because I knew it's similar to Shanghai. But it's just not as perfect as Shanghai is!