While existing WhatsApp users did not have a problem with the app working, users who wanted to sign-up for the app were left stranded as search results for the app on the Windows Phone Store returned the message "We couldn't find a match. Try a different spelling or search term.".
However, nearly two weeks later, on Friday, Joe Belfiore, who heads the Windows Phone/Tablet/PC product definition & design team, tweeted, 'WhatsApp is back. Happy Weekend'. He posted the tweet along with the link to download the app from the Windows Phone Store, which shows May 30 as the last update.
WHATSAPP IS BACK! HAPPY WEEKEND! Grab from here: https://t.co/MhNwf46hZs-- joebelfiore (@joebelfiore) May 30, 2014
Belfiore had taken to Twitter five days after the app had been pulled off the store to explain the reasons behind the same. He said, "For those w Q's on Whatsapp: they pinged us about an issue that popped on notifications, we're working with them on a fix. More info soon." On the same day he had tweeted again to explain the problem, "Ps - the notifications core in wp8.1 is different than wp8. The WhatsApp issue is in wp8 upd3. How's your wp8.1 notifications experience?"
According to reports, the problem was with update 3 for the Windows Phone 8 rather than the WhatsApp app itself. Something that was brought to the notice of the Windows Phone team by WhatsApp. The relaunched app has new features, which include chat backgrounds, custom notification tones (requires update 3 for Windows Phone 8), broadcast lists, media auto download, improved privacy settings and bug fixes.
It is important to note that WhatsApp is currently working on increasing its user base from the existing 500 million users to one billion in a year. It had announced last month that since February the user base had increased by 50 million users. This was post the revelation that Facebook would buy WhatsApp for a record $19 billion.