Howard Oakley always looks inside the packages to see what’s new. Here’s what he wrote about 11.5.1:
I have now had a chance to examine exactly what is in this update. There are no files with changed version or build numbers among the bundled applications (in /System/Applications), nor do any files in the System Library (/System/Library) have changed version or build numbers. The component which Apple refers to in its security note is a private framework, IOMobileFramebuffer.framework, which in Big Sur is built into one of the dyld shared caches in /System/Library/dyld, caches which are believed one of the reasons for Big Sur updates invariably being so huge.
There are no changes in the firmware in T2 Macs, and no change in the iBoot firmware in M1 Macs. The version information for the kernel is also unchanged between 11.5 and 11.5.1.
From what I see, the change made in 11.5.1 is so minimal that its size is a tiny fraction of the size of the update. In other words, almost every byte in the 11.5.1 update is overhead, not the update itself.
A somewhat ironic thank you to all who installed macOS 11.5 and helped to find and fix the bug that necessitated an 11.5.1 release. Was the bug introduced in 11.5? Are those of us hanging back on 11.4 safe?
Just for fun, and very roughly, if each update is 2GB larger than it should be, and there are roughly 100 million active Macs that will download the update any time soon, and (according to an MIT study) a 1GB download and active computer and peripherals cost 60CO2e grams, then those two updates cost an excess 24 million kg CO2e. That’s about 50 million miles of driving.
Don’t get me started. Yes I think we’ve all heard the goal to be Carbon Neutral by [insert future date here] but Apple has got to sack up and start moving towards the reliance on streaming content. Content Distribution Networks are running off of energy backbones that are anything but clean.
With local content storage being humungous the move towards “stream and store” has to happen.