The trend to bring communication services to multiple devices highlights a limitation that WhatsApp should address soon A couple of recent announcements/rumors have brought to my attention an acceleration of the “Multidevice trend”. In particular: , and one of the interesting pieces is that SIM-enabled version supports regular phone calls and SMS. In fact for which it highlights that Google has recently announced their Android Wear 2.0 version Verizon is launching a specific device “These smartwatches are always connected to your smartphone’s phone number, so texts and calls from the watch use that number, even if the smartphone isn’t with you. This makes it ok to leave your smartphone in the other room or go out for an errand without it and keep up with all your notifications. ” One number, multiple devices. On the rumor space, the expectation is that . both Amazon and Google are planning to enable regular phone calls support in their connected speaker products Both initiatives align quite well with a recent resurgence of this “One number, multiple devices.” approach to traditional communications. Telcos betting on multidevice operators traditionally saw the phone service and identity as something phisically tied to the SIM card, so the ability to bring the phone number to several devices was tied to and required the devices themselves to be SIM-enabled. Mobile MultiSIM service offerings This limitation has been overcome by some operators that have started — some quite recently — to provide access to the communication service across multiple devices without requiring a SIM Rogers in Canada, pioneered this space with their . They offer the ability to make and receive calls and texts across several devices and connectivity based on VoIP applications. It is curious to see that now that this is being followed by lots of other operators, . The justification is that native Wifi calling support appearing on more devices makes this offering no longer relevant. I personally disagree with this consideration, because — as I wrote in Medium some weeks ago — . However I don’t have numbers on how Rogers’ product was performing to make a proper assessment, and they have certainly done their own analysis to take this decision. OneNumber service launch in 2011 Rogers has decided to close down their service owning the customer experience is becoming increasingly critical , in which I have been quite involved personally, was , and from there expanded to other operators like or . TU Go follows a similar approach to OneNumber, but in this case not considering native capabilities in devices as an alternative, but . Telefónica’s TU/TU Go launched by O2 in 2013 VIVO in Brazil movistar in Argentina something that can complement the offering , but their non-SIM offering is limited to Apple devices, using iCloud as the way to propagate the phone identity across them. For other devices, like some tablets and Smartwatches, the solution uses a MultiSIM approach based on the SIM identity. AT&T launched NumberSync in 2015 Android , announced by the end of 2016, and in their case they are following a mixed approach — which I believe is the right one — based on providing apps and web capabilities to enable the capability in practically any available device, but then : Digits is the T-Mobile offering work with some partners to leverage some natives experiences DIGITS will run natively on Samsung Galaxy S6, Galaxy S6 edge, Galaxy S6 edge+, Galaxy S7, Galaxy S7 edge, or Note5 purchased through T-Mobile. They already have DIGITS integrated directly into the devices right out of the box. No software download required To most people these concepts of extending the calling funtion beyond the phone, specially considering getting your calls on a watch, can bring, maybe fond, but definitely impractical memories: I end up doing this much more than I originally expected But to this I have two considerations: Don’t think about wearables: It is extremely useful that computers, tablets or Wifi speakers are able to work with your regular calls. For convenience, productivity or backup, having that ability helps overcome some limitations of the physical phone. What the heck, let’s think about wearables! I was skeptical of calls in a watch too, but I must confess that this is one of the capabilities that I have ended up using a lot on my Apple Watch. I though I would never need to do that, but answering an incoming call while you are doing some activity and your phone is around but not at hand is really convenient. That is the current Apple Watch behavior, which relies on the phone being close for this to work, but as i discussed in a previous article, . If the dependency to the phone is broken, and we begin to talk to our watch not by raising a wrist but through wireless earbuds, communications in a wearable device will make a lot of sense. the trend for the phone disintegration keeps progressing Most Internet Communication Services are ready for this The origin of Internet communication services is tied to the computer as a device. Of course the PC is not a phone, but originally in most cases wasn’t even really “personal”. Many people shared a PC at home, or used the ones in Internet cafés for communications. In this context, services like Skype or MSN Messenger were designed with multidevice considerations almost unconsciously. Unfortuntely, this multidevice approach considered only PCs as devices, so when they tried to transition to mobile, they were not able to provide the best experience and other applications beat them. Facebook Messenger also supports multidevice, in part as a testament of their Web origin. Messenger was not a mobile-first service, but it has been able to transition succesfully into mobile. Interestingly enough, one of the key aspects for this transition was to , following WhatsApp approach. allow users to sign up with a phone number instead of a Facebook account Other mobile-first services have also strong multi device design from the beginning, and allow you to use your comms across several devices, like Apple’s iMessage (though only Apple devices are enabled) or Telegram. Telegram platform support is actually multidevice oriented (source www.telegram.org) But that is not the case for WhatsApp. Mono-device at heart WhatsApp mobile-first approach has been an excellent way to provide a simple yet powerful communication experience. As a “SMS 2.0”, it did not try to do something different than SMS messaging (which is also designed for a single device), just make it better. In fact the single-device focus can be perceived as a security capability, as when you install WhatsApp in a new device, and do the registration, it will stop working on the old one. This prevents someone using your communications if you lose your phone as soon as you register in a new one. And if someone was able to replicate your SIM card to supplant your number, you would identify that because your WhatsApp service would stop working. WhatsApp over time too, and their bet to bringing end-to-end encryption to the masses is a proof of that, even if . But the way they have chosen to implement this makes even more difficult to consider how to bring the WhatsApp experience to additional devices without having to depend on the phone. It is not impossible, as , but it would be a significant change for WhatsApp. focus in security has been increasing some of their UX decisions around that have driven some (in my opinion unfounded) recent criticism Apple supports end-to-end encryption in iMessage with multi-device support Their current desktop versions are actually a testament to this, as they have been implemented (maybe forced to implement?) in a way that makes them dependant on your phone running WhatsApp too: This brings the advantage to the Web of immediately leveraging the mobile device comms history storage, address book and e2e encryption. But it comes with the price of inefficient data and battery usage, and makes functions like voice calling or video calling, available in the phone, very hard to be brought to the desktop. The Achilles Heel So if the trend of multidevice keeps expanding ( , but this will change with cellular connectivity as battery life issues are solved) and the becomes a reality, WhatsApp may be seriously impacted. People will feel more comfortable leaving the phone at home, because they are connected by other available devices, and a communication service that only works in a single one will become too limited. smartwatches sales today may seem discouraging disintegration of the smartphone WhatsApp could try to follow a similar approach to what they are doing in Web for new devices, still relying on your phone being connected and charged *somewhere*, but this does not seem a scalable approach. Otherwise this may become their achilles heel, as users switching their communication behaviors to wearables, connected speakers or other devices will have to leave WhatsApp behind with their phone. I think WhatsApp should start redesigning its solution and future-proof it by considering how to properly expand to multiple devices.