ios upgrade caused unnecesary and costly obsolescence of my trusty Macbook pro
my Macbook currently running on ios 10.10. how do I upgrade it to 10.11?
Question marked as
Depending on what your first statement means,
the second part, maybe, takes another direction.
..While I'm offering information, per the path to upgrade;
I know nothing of what you did, nor any resulting actions.
The Mac system is called macOS. While the iDevice
(non-mac) system is called iOS & has sub-sections.
There are various older macOS installer downloads
and instructions, that need to be followed exactly.
• How to get old versions of macOS - Apple Support
https://support.apple.com/en-us/HT211683
These are kind of grouped into old and older versions.
And the instructions to use them, are too.
Before any invasive actions are taken, there should be
backed-up (at least 2 or 3) on external drives; & Tested.
Backups are 'common theme' for user's Mac OS survival.