Oh dear. Of all the days to suffer an outage, if you’re the world’s most popular messaging app WhatsApp, you probably wouldn’t have chosen New Year’s Eve, with millions of people, young and old, around the world, turning to the app to send messages of goodwill to friends and family. Only to find they can’t.

The problems began around 4.30pm UK time today. The service was back up within the hour, but then crashed again, though as we write this, based on a couple of test messages sent to friends, the service appears to be back up. Whether it will stay up as midnight continues to kick in around the globe, however, is a moot point.

The outage completes a slightly miserable end to a stellar year for WhatsApp’s owner, Facebook. Last month, the company posted revenues of $4.5bn (£2.9bn) and profits of £1.5bn for Q3 2015, with most of the money coming from advertising, and most (78 per cent) of that coming from mobile.

In addition to the WhatsApp outage, however, Facebook also learned on Tuesday that two class action lawsuits being brought by shareholders against Facebook in the US can go ahead, following a ruling by a federal judge. The lawsuits date back to Facebook’s IPO in 2012, and allege that it concealed concerns over its future growth ahead of the listing. As a result, the claimants say, the shares were overpriced, meaning that they lost money in the process of buying them.