https://www.ifixit.com/News/14279/apples-diabolical-plan-to-screw-your-iphone

"Apple is switching to a new type of tamper-resistant screw. This is not a standard Torx, and there are no readily available screwdrivers that can remove it. This isn’t the first time they’ve used this type of screw—it first appeared in the mid-2009 MacBook Pro to prevent you from replacing the battery—and Apple is using a similar screw on the outer case of the current MacBook Air. This screw is the primary reason the 11″ MacBook Air earned a lousy repairability score of 4 out of 10 in our teardown last October.

Apple chose this fastener specifically because it was new, guaranteeing repair tools would be both rare and expensive."


https://en.wikipedia.org/wiki/Pentalobe_screw

The pentalobe security screw is a five-pointed tamper-resistant system used by Apple. Pentalobe screws were adopted by Apple starting in 2009. Apple attracted criticism upon the introduction of the pentalobe screw; it was seen by some as an attempt to lock individuals out of their devices. In response, inexpensive pentalobe screwdrivers, manufactured by third parties, have become relatively easy to obtain.