Telegram, a messaging app that emphasizes privacy and security, added millions of new users Sunday, following WhatsApp’s biggest outage in years. The spike in downloads pushed the app to the No. 4 position in the App Store Sunday and the app was the No. 1 iPhone app in 48 countries, according to the company. The outage appears to have boosted Telegram’s downloads considerably. By Sunday afternoon, the company was reporting it had added 4.95 million users on that day alone.