Following EE, O2 and Three, Vodafone is finally ready to launch its own WiFi calling service. It's rolling out nationwide over the next few weeks and will be available to anyone with a Vodafone Red, Red Value or Red+ plan -- provided you have a compatible device, that is. So if your home is trapped in a "not-spot," or you frequently use the London Underground, people can still get a hold of you -- avoiding a string of missed call notifications when you next stumble upon some coverage. Like EE, Vodafone's service will kick in automatically and doesn't require a separate app. Once your account is activated -- presumably Vodafone will send you some sort of alert -- it's just a matter of enabling it in your phone's settings. Our main concern now is device compatibility. Vodafone says it'll be supported on "a number of leading smartphones," which hopefully means more than a select few.