Nonetheless, many Londoners didn’t obtain the alert — and never solely those that have disabled the characteristic. Listed here are among the causes your telephone might not have sounded the alarm together with everybody else.
You’re on the Three cell community
Many individuals who didn’t obtain the alert check have one thing in widespread: they’re on the Three cell community.
Three has acknowledged there was an issue with its supply. “We’re conscious that a variety of clients haven’t acquired the check alert,” the corporate wrote on its official Twitter account. “We’re working intently with the Authorities to grasp why and guarantee it doesn’t occur when the system is in use.”
No official follow-up rationalization has been given, however one principle posited by developer David Wheatley on Twitter was that Three’s implementation was merely completely different from different networks.
“Networks who efficiently carried out the trial did rebroadcast the signalling (SIB12-v920) constantly for the total 20-minute length of the check, stopping the alert at about 15:21,” he wrote. “This meant, for those who had a tool in airplane mode till 15:15, you’d nonetheless get the alert.”
Against this, Wheatley’s evaluation suggests Three despatched the alert solely as soon as. This meant telephones not actively searching for the sign throughout that transient window can have missed it. “Units don’t always search for these messages, therefore why they need to repeat,” he mentioned.
You weren’t related to 4G or 5G on the time
The emergency alert system depends on 4G and 5G connectivity. In case your telephone was in an space with out reception — both within the sticks with 3G connectivity, or beneath floor and not using a good sign — then the alarm merely gained’t have sounded.
This additionally applies in case your telephone was on airplane mode on the time of the alarm, too.
Your telephone’s working system is outdated
Whereas each Android handsets and iPhones can obtain emergency alerts, they must be fairly up-to-date to take action. iPhones should be working iOS 14.5 or later. Whereas the iPhone 13 and 14 had been shipped with the characteristic able to go, earlier handsets would want to have been up to date sooner or later within the final two years. Handsets earlier than 2015’s iPhone 6S are incompatible.
Android gadgets, in the meantime, should be working Android 11 or later. That model arrived in 2020, although older variations “should still be capable to obtain alerts”, the Authorities says.
You’ve disabled emergency alerts in your telephone
Some individuals disabled emergency alerts on their telephone earlier than the check. This was over fears that the characteristic could be abused or that it’s an indication of Authorities overreach.
That is very laborious to do by chance, nonetheless, requiring you to dig into your telephone’s notifications settings menu to decide out.