Want to update to Yosemite 10.10.5 (NOT El Capitan)... how?

OK... so... My $3000 Mac Pro is officially obsolete?...

And I can't use any of the software that's incompatible with El Capitan?

So as of 2016, Apple simply doesn't care about pro users who require a specific OS version.

"Apple has withdrawn 10.9 Mavericks and 10.10 Yosemite for sale as new, If you have not already downloaded them"
Wow, that's completely out of touch with the way creative professionals, dependent on software version compatibilities, use Macs in general.

"Apple considers 10.11 ElCapitan vastly superior, and does not want you to adopt older Mac OS X when better solutions are already available"

Of course they consider it superior - it's newer, it better be superior, that's what they're paid to do! But calling it a "better solution" when clearly it isn't for people stuck to older software to finish deliverables... it's just out of touch. I thought Apple was all about user research and making things easy to use... well they forgot to research pro users :/

"This is not an issue with the Mac"
It is! Sorry. I bought pro hardware so I could use it no matter what, in the way I see fit. Apple limiting my freedom to install ANY OS version absolutely created a MAJOR issue with all Macs.

"it is an issue where Avid Pro Tools has not yet adapted their software to the latest releases of Apple system software."
I have to pay a lot of money to update to Pro Tools 12, which a lot of musicians and studios haven't done because it's not worth it. Look, we could go on and on, but the bottom line is, Apple won't let me install THEIR OS on THEIR hardware, simply because "there's a newer version".

Because of this philosophy, my $800 original Retina iPad is today completely unusable (Apple kept automatically installing iOS updates and not allowing me to ever revert) and now the device doesn't run, it crawls.

"I suggest you contact Avid are ask them to guide you."
How is it Avid's fault that Apple decided to adopt a fascist policy about installing OS versions? lol

Whoever at Apple decided OS X updates should be handled like iOS updates, needs a new job. There's a good reason why people use computers still today, instead of just "apps" on cute mobile devices. That reason is productivity. Apple seems to have forgotten what that was.

"If you have unusual requirements"
Only considered unusual if the "usual" is teen girls playing Candy Crush on their iphones.

"you are welcome to make a free appointment at the Genius Bar, and request them to install any older version you need."
Transport a 50 pound Mac Pro to the store, simply because I was too busy last year to make a pretend "purchase" and trick App Store's restrictive system? No thanks.

Maybe it would make more sense to update to El Capitan, as Apple demands me to, then send them the bill for the Pro Tools 12 update. If it hurts their pocket instead of mine, maybe they'll think about it next time they restrict users.