If you have a valid Zoiper 3.5 Pro license, by all means, continue to use it—it remains one of the most reliable softphones ever written. But if you are a new user looking for a place to start, download the latest free version from the official Zoiper website. The nostalgia of 3.5 is not worth the security headache.
While it has been superseded by modern versions that add video, messaging, and better security, Zoiper 3.5 is remembered fondly by VoIP professionals as a tool that "just worked." For anyone studying the evolution of VoIP clients, it remains a perfect example of pragmatic, feature-focused software design. zoiper 3.5
Zoiper has been available in two primary editions: If you have a valid Zoiper 3