Kirstens S21 184.108.40.206 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free software for Mac OS X is an intellectual property of Kirstensviewer. The most popular version among the program users is 2.8. The unique ID for this application's bundle is com.secondlife.indra.viewer. The program is included in Design & Photo Tools. Commonly, this program's installer has the following filename: Kirstens-S218-OSX Intel.zip.
From the developer:
Opensource Created Custom Viewers For Virtual Worlds like SecondLife.
The S21 viewer is based on S20 and viewer-development codebase. This is current and has all the functionality available in the official viewer 2.0. This client forms the basis of the next generation of 2.0 based clients.
S21 has modified rendering and various differences from the offcial client actively developed.
You may want to check out more Mac applications, such as UltFone WhatsApp Transfer, which might be similar to Kirstens S21.