✅ : WhatsApp works inside your browser window. Keep your phone online.
However, you have two practical workarounds. Since the dedicated app won’t install, use WhatsApp’s web client. The challenge: old browsers on Lion (Safari 6, old Firefox/Chrome) may not work. Here’s how to succeed: download whatsapp for mac os 10.7.5
Open WhatsApp on your phone → Settings → Linked Devices → Link a Device → Scan the QR code on your Mac screen. ✅ : WhatsApp works inside your browser window