Which Pentalobe screws are interchangeable from model to model?

iPhone 5 screws are 3.6mm and 5s/SE2016 are 3.9mm, according to iFixit. However, iFixit sold the same replacement pentalobes for 5/5s/SE, suggesting that they can still use the same screws, despite them being different lengths. 5c screws are different from the rest. 5/5s/SE screws are built with 3 sections - head, shaft without threads, shaft with threads at the bottom. 5c screws have a very thick head followed by a fully threaded shaft.

6/6+ screws are the same, but different from 6s/6s+ and 7/7+. The difference between 6/6+ and 6s/6s+ is in length. The iFixit guide for 6+ states the screws are 3.6mm in length. According to the measurements supplied by a third party vendor, 6/6+ screws differ from the iPhone 5 screws of the same length by having a thinner head (0.416mm vs 0.424mm).

Guides for 6s+ and 7+ state the lengths to be 3.4mm and they have the same number of threads and threads in the same position so I believe these are the same. However, I have seen these screws sold as different items on vendor sites, so I can't say with 100% certainty that they are exactly the same, but that they are similar that they should work interchangeably without issue. Plus and non-plus models have the same pentalobes in all series.

8/8+/SE2020 (and probably SE2022 but I haven't come across any of these devices yet) are the same (3.5mm, according to the iFixit guide). Note that previous generations had the threads at the bottom, 8 series has the threads at the top of the screw. If you put previous generation screws in an 8 they will be difficult to remove as the threads do not match.

X and everything above released to date (13 series) bottom screws are all compatible. Of course, not all models come in the same colours, but the screws themselves are physically the same.