Apple has updated one of its earlier operating systems so the UK's contact-tracing apps can now function on older iPhone models.
In theory, the apps are now able to work on the iPhone 5S, launched in 2014, and 6, launched in 2015.
The developers of the three apps - for England and Wales, Scotland and Northern Ireland - will also have to make upgrades, however.
And the changes they need to make are unlikely to be ready until January.
Apple announced the update on its website, saying: "iOS 12.5 lets you opt in to the Covid-19 Exposure Notifications system for your iPhone.
"System availability depends on support from your local public-health authority."
When the NHS Covid-19 app was launched, there was one major complaint: "Why can't I get it on my older iPhone?"
It was a question asked by millions, many of them elderly phone users, even though the Department of Health insisted nine out of 10 smartphone owners would be able to install the app.
The problem wasn't the app developers' fault - the underlying Exposure Notifications system built by Apple and Google just did not allow iPhones older than the 6S to access the iOS 14 operating-system update necessary to make things work.
Now, a bespoke update - iOS 12.5 - should in theory mean all those proud owners of the iPhone 5S and 6 can now get the app.
But hold on - it's not quite that simple.
There's work to be done first to upgrade contact-tracing apps using the system.
Even Apple thinks that won't be done before January.
And the NHS app developers will have to decide how big a priority it is among many other features they are working on.