Older PPI blades users know all PPI blades used to be double wrapped back in the days. Later around 2012-2013 they dropped the paper envelope and you had only wax paper. In 2017 all of their blades got the new Gillette logo and most of them had the ©2017 on the back of the packs. Inscription with the blade name appeared on the wax paper.
I have been using for years the 7 O'clock Sharpedge. The ones I use currently were bought in 2011, double wrapped - the left on the photo.
A couple of years ago I bought the new design - ©2017, on the right of the photo (manufactured 10/20). Back then I just used one blade and it felt significantly milder than the old double wrapped stock. I remember someone else saying the new stock were less sharp.
So I did this comparison. Two consecutive days with the same razor (ATT Windsor Pro Aluminium), tube and brush. I am 100% positive the blades are quite different. On pass 1 WTG the difference is not very noticeable. On pass 2 ATG the newer blade displayed some resistance in the moustache and goatee area. Third pass XTG and this is where the newer blade struggled on my neck. With the older blade everything is like a song. And the final result is a significantly closer shave.
So, in the next months I will have to compare all PPI models old double wrapped vs the new post 2017.