The new 3CX v20 Softphone replaced the old Electron desktop app to offer better security while preparing for future market endeavors. The previous Windows Electron client used a lot of libraries and framework that was hard to maintain, update, and could be vulnerable, so 3CX completely rewrote the software. The new Windows softphone client is now independent from web browser updates and is only deployed via the Microsoft store, offering another layer of security and testing.
The new native 3CX Windows softphone will act as a “SIP Client” (similar to the iOS or Android app), and will run in conjunction with the web client. As a native softphone, audio control will be independent from the browser to offer a proper answer dialog.
Further details can be found on 3CX’s blog post at https://www.3cx.com/blog/releases/windows-softphone-beta3/.