Aperture 3.5.1 was a bridge between the older Mac OS X 10.8 (Mountain Lion) and the newer 10.9 (Mavericks).

Where can I find an Aperture 3 download f… - Apple Community

: Resolved a bug where the Temperature and Tint White Balance controls did not function correctly.

Aperture 3.5.1: A Guide for Modern macOS Users Apple released Aperture 3.5.1 on November 15, 2013, as a critical stability and bug-fix update following the major release of version 3.5. Although Apple officially discontinued Aperture in April 2015 to make way for the Photos app, many photographers still seek this specific version to maintain compatibility with older macOS environments or to preserve specialized professional workflows. Key Features and Improvements in 3.5.1

: Fixed issues with face detection overlays that prevented them from displaying properly.

: Corrected a flaw that caused metadata fields to remain empty or fail to update when using arrow keys to move between photos.