By choice I've kept using OS X 10.9.5 Mavericks on my computer to use Photoshop CS6 and Lightroom 4. Early on I heard there were issues with OSX upgrades. What sort of technical complications will I encounter if I upgrade to OSX El Capitain with CS6 and LR4? Is ACR the same version in CS6 and LR4? Thanks for helping.
The ACR plugin in Photoshop CS6 can be updated to version 9.1.1.
Each version of Lightroom has the equivalent of ACR built into the application and cannot be updated. The latest version of Lightroom 4 is version 4.4 and is equivalent to ACR 7.4.