How will I know that the 83-115 will work on my door?

Need to replace the latch on my Pella wooden sliding screen door. Latch 83-115 seems to be the correct one, but I read somewhere that Pella redesigned this latch some time ago to be longer and the older design is no longer available. My understanding is that longer latch will not work in "older" (?) doors. Only have a portion of my broken latch and cannot measure the overall length which seems to be the critical dimension. How do I know, or can I know, if the new design (length = 3 7/8") will work on my older screen door?

Thanks for the response Tom. I do have another Pella sliding door with the same latch so I took it apart to examine and measure the latch. My latch (old one) is only 3" long, not 3 7/8" as shown in your detail. After examination I believe the only difference is the length of the thumb depression end of the latch. When installed, the part of the latch that is inside of the mechanism housed in the wood frame appears to be the same for both new and old latches. The only difference being how far the thumb depressor extends out of the wood frame. I ordered a new latch yesterday hoping my analysis is correct because it appears I have no other option. Thanks again for your quick response.