Test your audio. Because 3.7 is older, you may need to manually adjust codecs in the settings to match your provider's requirements. How to install and use Zoiper 3 with ILLYVOIP
Upload the downloaded file to a free online scanner like VirusTotal before running the installer. Zoiper 3.7 Download
After the installation finishes, launch Zoiper immediately. Test your audio
This is the most critical section. Because Zoiper 3.7 is a legacy version, you will not find it on the official Zoiper website (which now offers version 5.x or higher). Instead, you must rely on trusted third-party repositories or your own archived installers. Zoiper 3.7 Download