I started this post, because I was confused about the date code format, I was wondering if for some reason they went to YYDDD at some point, but after I posted the pictures I realized that the one with the seemingly off date code format is the same as the other it just has a numeric plant id rather than a letter I guess, the top filter was new in a sealed 2017 copyright box, apparently manufactured the 98th day of this year. The other 2 came from a lot of 5 I got from a guy off eBay, he had sold the car he used them on and didn't need them any longer, I guess he opened the box to make sure they weren't defective or something, which is what I do when I buy filters if they're going to sit for a while, they had copyright 2013 boxes. The one was apparently manufactured the 204th day of 2013, note the Fram oil change sticker included in the box, the other 4 were throwing me off on the date code, because I seen the one at the beginning and thought, there's no way this filter was manufactured in 2011, so I wondered if they switched to a 2 digit year code for a while or something and they were manufactured in 2015, although just as I was going to post this I realized the 1 should be the manufacturing plant ID and 5 should be the year, so they were manufactured the 82nd day of 2015. I didn't really need to post this but I already went to the effort to take and paste the photos, so eh.