Run it in Windows 8 Compatibility Mode. Right-click Viber.exe → Properties → Compatibility → Run this program in compatibility mode for Windows 8. Also check "Disable fullscreen optimizations."
127.0.0.1 update.viber.com 127.0.0.1 cdn.viber.com/update viber old version windows 10
While the Official Viber Website only provides the latest version (e.g., v22+), you can find archived builds on reputable third-party repositories: Run it in Windows 8 Compatibility Mode
Reviewing older versions of for Windows 10 reveals a software history defined by a transition from a lightweight, "Beta" utility to a feature-rich (but often resource-heavier) desktop application. Core Functionality & Evolution viber old version windows 10
Here are the common highlights found in positive reviews for older Viber builds: Lightweight Performance