Adobe Photoshop CC 2015 v16.1.2 was one of the last major versions to offer robust support for both 32-bit (x86) and 64-bit (x64) Windows architectures. Can I get Photoshop CC 2015 still? - Adobe Community

The 2015 release introduced tools that fundamentally changed how designers approached digital canvases:

: Photographers gained the Dehaze filter in Camera Raw to remove (or add) atmospheric fog. Additionally, the Content-Aware technology was integrated into the Crop tool, allowing Photoshop to intelligently fill in gaps when rotating or expanding a canvas. Technical Specifications and Support

: Perhaps the most significant addition for web and mobile designers, Artboards allowed for multiple layouts of different sizes within a single document. This allowed creators to see how a design looked across desktop, tablet, and mobile screens simultaneously.