Just two weeks after accusing WhatsApp of lying, to 2 billion users, Telegram has serious new problems of its own. The huge rival messenger has suddenly released a surprise update for millions of iPhone usersand this one looks like really bad news.Serious new warning issued for millions of Telegram users.gettyIt has been one of the standout tech battles of 2021, and while it might not have the celebrity standing of Zuckerberg versus Cook, the spectacle of Telegram and WhatsApp trading blows on social media is certainly compelling viewing.The battle between the worlds leading messaging platforms has never been more intense. Facebook commands the space, with WhatsApp and Messenger, but in the U.S., iMessage enjoys more market share, a source of real contention for Facebook. Meanwhile, rivals such as Telegram and Signal have been on a growth tear in the wake of WhatsApps privacy backlash earlier in the year. That backlash may now have been framed by the forced change of terms WhatsApp threatened to inflict on 2 billion users before it backtracked, but it started with the release of Apples privacy labels.As you will no doubt remember, WhatsApp (and Facebook Messenger) come across very badly when those privacy labels are compared across the leading platforms. There is too much data, across too many categories, and everything collected is linked back to user identities. Signal, Telegram and iMessage present very differently.MORE FROM FORBESYes, WhatsApp Confirms Surprise New Update-Here's What You Do NowBy Zak DoffmanSince then, Telegram has campaigned to keep WhatsApps awkward data sharing with Facebook in the headlines and users minds, while WhatsApp has mounted a full-scale PR blitz to emphasize its security and privacy credentials, centered on its end-to-end encryption that keeps Facebook (and everyone else) out of user content.Given that Telegram has relentlessly campaigned against WhatsApp on privacy grounds, accusing its rival of misleading users, its somewhat awkward that Telegram has suddenly updated its own privacy label. And now its not looking so good.Privacy Labels: Telegram Before and NowApple / @UKZakWhere before it collected basic contact info, contact lists and an identifier, now it has added purchase histories and financial information, precise locations, and user content, including email and text messages, audio and media.While the major caveat with privacy labels is that they represent the worst casenot all labels are collected for all users, this has clearly been done reluctantly, and more importantly, all this data links back to users and their identities. And so, while Telegram is still clearly collected significantly less than WhatsApp, the differences between itself, Signal and iMessage are now much starker.For its part, Telegram is clearly irritated at Apple, which is being rather unreasonable with their interpretations, I was told. But data is data, and this is another example of messengers becoming multifaceted platforms, providing finance and commerce, compromising the security and privacy of core messaging to do so.Telegram has published an explainer on Apples privacy labels, assuring that we don't use your data to track you or show you ads; we don't use your data to help others track you or show you ads; we only store the data that Telegram needs to function as a secure and feature-rich messaging service, for as long as you need it.MORE FROM FORBESFacebook Tracks Your iPhone Location-This Is How To Stop ItBy Zak DoffmanOn the specifics of the new labels, Telegram says that the purchases, financial information and location fields may be either misleading or irrelevant, only coming into play when a user selects certain features or functions. The critical new field is user content, though, and that does point to a security and privacy issue that sets Telegram apart from the likes of WhatsApp and Signalits cloud service. Telegram is not end-to-end encrypted by default, with limited exceptions, user data is stored on its cloud platform and can be technically accessed by staff. With Telegram, you are trusting their reputation and policies to keep your data private and secure, you are not trusting the integrity of their end-to-end encryption. Thats a huge difference.Telegram is a cloud service, it says. We store messages, photos, videos and documents from your cloud chats on our servers so that you can access your data from any of your devices anytime without having to rely on third-party backups. All data is stored heavily encrypted and the encryption keys in each case are stored in several other data centers in different jurisdictions. This way local engineers or physical intruders cannot get access to user data.That may sound goodbut its not end-to-end encryption. Put simply, your content is only encrypted between your device and Telegrams cloud, and Telegram has the keys to decrypt it. There is no technical impediment to it doing so. That is significantly different to the security being offered by others. make sure you understand that.Is the privacy label update a game-changer for Telegrams iPhone users? Nonot in itself. But it highlights an issue that should be a concern for 500 million users.More importantly, though, just two weeks after taunting WhatsApp over its change of terms, the timing of this update is a real issue for Telegram. While WhatsApp is notably quiet on the subject of Signalwhich has also poked its larger rival over the privacy backlash, the Facebook messaging giant has come out on the attack against Telegram, to remind users of Telegrams security shortfalls.I dont like the idea of secure messengers capturing precise locations and linking those to user identities, to say nothing of multiple identifying fields. But then Telegram isnt a secure messenger, not really. And thats the crux here. Yes, you can continue to use Telegram on your iPhone, but dont buy into its marketing. Its not as secure as Signal, its not as secure as iMessage, and its not even as secure as WhatsApp. And so, leaving WhatsApp for Telegram over security or privacy fears is nonsensical. Dont do it. Period.