Earlier this year, WhatsApp introduced web client for Android and now the web client is rolled out for iPone users. The web client for iPhone is available through a server-side update, so it will be pushed out automatically if you don’t have it yet. To use the WhatsApp Web client for iPhone, you have to go in to WhatsApp settings in iPhone app, after that select WhatsApp Web and san the OR code that you get when you visit web.whatsapp.com form the desktop.
Recently, it got updated to v2.12.5 with per char custom notification settings & mute, videos in chat backups and lots of more features. WhatsApp for iPhone got calling feature in April and it has 800 million monthly active users as of April & remains the fastest growing messaging app.