When is Lightroom CC 4.2 will be released with Sony Alpha 1 Raw support?

If you need to edit Alpha 1 images right now and can't wait for the release of 4.2, your best bet is to use Adobe's dng converter (https://helpx.adobe.com/photoshop/using/adobe-dng-converter.html ), which has been updated to support Alpha 1 images to convert your raw files to dng raw files and those will work fully in Lightroom 4.1. They're also only half the size of the arw files while retaining 100% of the quality because dng files use much more efficient lossless compression than Sony does in their cameras.

Lightroom 4.2 hasn't been released yet, but is expected shortly.