Thank you.  Why don’t you upgrade to Catalina, (10.15.x) instead?

https://eshop.macsales.com/guides/Mac_OS_X_Compatibility

That's mb its a "late 2012" 27" iMac, do you need the serial #?

If only you told us the model of the Mac you have...

I recently picked up an old mac for cheap to use as sort of a dump pc. Sadly the os has not been updated since it was new and I can't seem to find anything in the iTunes updates to update the system. I need to have the system be at least 10.9 to run certain programs. 

Thank you for any help you can give.

Upgrading from MacOs 10.8.5