Calm calm; You are not reading wrong. Today really October 27th 2019 and yes we're talking about the iPhone 5.
The news that owners of this generation of iPhone should upgrade to the iOS 10.3.4 Released last July on iOS 12.4 no later than November 3, otherwise we will no longer be able to access the App Store, iCloud, emails, the web and other services.
Remember that iOS 11 onwards is no longer compatible with iPhone 5, so this is the last version that can be installed on it.
As Apple explains in a new support article:
Beginning at 12:00 AM on November 3, 2019, iPhone 5 will require an iOS update to maintain accurate GPS location and to continue to use features that depend on the correct date and time, including App Store, iCloud, emails and web browsing. This update is required due to the GPS timing issue that began to affect third-party GPS products on April 6, 2019. Apple devices with this issue will not be affected until just before 3:00 AM UTC. November 2019.
That is, if we are talking about 0h UTC, Brazilians will actually have to upgrade until 9 pm on November 2, 2019 otherwise they may have serious problems.
To upgrade iPhone 5 to iOS 10.3.4, the same as usual: just open the Settings app and go to General Software Update. For those who prefer, here is the direct download link for IPSW.