Quote from the Lightroom Journal when the latest update to ACR 8.3
"Camera 8.3 for Photoshop CC and Photoshop CS6 available now
Posted on December 11, 2013 by Sharad Mangalick | Comments (17)
Camera Raw 8.3 is now available as a final release for Photoshop CS6 and Photoshop CC. This release provides new features including Auto Levels-like functionality and Auto Straighten. In addition, this release also includes bug fixes, support for new cameras and new lenses. DNG Converter 8.3 is provided for customers using versions of Photoshop older than Photoshop CS6.
As mentioned here, updates to Camera Raw 8 for Photoshop CS6 only include new camera support, lens profile support, and bug fixes. The new features listed in the release notes are only available in Photoshop CC.
Please note that this is the final version of Camera Raw 8 and DNG Converter 8 that will be available for Photoshop CS6 customers on Windows XP, Windows Vista or Mac OSX 10.6. Impacted customers can continue either update to compatible operating system or continue to use Camera Raw 8.3 for Photoshop CS6. Photoshop CS6 customers on Windows 7, Windows 8, Mac OSX 10.7 (Lion), Mac OSX 10.8 (Mountain Lion) or Mac OSX 10.9 (Mavericks) will not be impacted and will continue to receive updated camera support through future ACR 8.x dot releases.
New Features in Camera Raw 8.3
Auto straighten: You can automatically straighten a picture in three ways: (1) double-click on the Straighten Tool button icon in the toolbar, (2) with the Straighten Tool selected, double-click anywhere within the preview image, and (3) with the Crop Tool selected, press the usual command key (on Mac) or control key (on Windows) to temporarily switch to the Straighten Tool, and double-click anywhere within the preview image.
Whites and Blacks now support Auto Levels-like functionality via shift-double-click on the sliders.
Added separate Auto Temperature and Auto Tint feature. Shift-double-click to invoke “auto temperature” and “auto tint” separately.
Added feature to set the background color of the work area and toggle the visibility of the hairline frame around the image. Context-click outside the image in the work area to select an option from a popup menu.
Added option-click shortcut in Synchronize, New Preset, Save Settings, and Copy/Paste (Bridge) dialog boxes. Option-click a checkbox to check that box exclusively. Option-click again to toggle previous checkbox state.
Added Camera Matching color profiles (Natural, Muted, Portrait, Vivid) for the following Olympus cameras: " End Quote.
The above explaines how the latest ACR Plugin 8.3 affects Photoshop CC and Photoshop CS6 users. Note that some of the new functions that a provided will work with PS CC but not PS CS 6. All these new features are available in LR 5.3 since this version if fully compatable with ACR in PS CC.
Since there is this incompatablety between LR 5.3 and PS CS6 you will get the error message.
If you choose render using Lightroom all your adjustments will be applied to the raw data and a tiff file will be sent to PS CS6.
If you make the choice to render anyway ACR in PS CS6 will render the file and open in PS CS6 (however if there are any adjustments made utilizing the new features of ACR 8.3 they will not be applied.