If you ask the average user, they will install the latest version of 4K Video Downloader or YTD. So why are you, and thousands of others, specifically hunting for version 2.1.6 ? Here are the top reasons:
Youtube app version 2.1. 6 : Free Download, Borrow, and Streaming : Internet Archive. Internet Archive Video Downloader professional - Download
Security firms (Kaspersky, Malwarebytes) have analyzed thousands of "old YouTube downloader" installers. Over 60% contained hidden cryptocurrency miners. The software runs silently in the background, using your CPU to mine Monero. You will notice your laptop fan spinning constantly and your electricity bill rising.