Bag revisions

Hi
Is there any page which lists the evolution of a particular bag?
Like first release date, when and what changed in the updated design etc....

I cannot answer your question directly, but I have researched this type of thing myself three ways.
The first is back reading forum posts.
The second is back reading blog posts.
The third is using the way back machine.

I have been able to find out when o-rings were added, what colors were offered and when, and if any dimensions have changed. Best of luck.

Thanks...I was interested in the Zephyr and found that there was at least one revision where the back zipper was expanded to allow it slide over larger roller bag handles.