Unfortunately if you are using an older iPhone, it seems that Siri Shortcuts might have limited functionality on your device, if it works at all. This is according to a post on Reddit (via VentureBeat) in which developer Federico Trevisani discovered that the Siri Shortcuts app consumes a fair amount of system resources where it is possible that some of its features might not work on older iPhones.
He reached out to Apple SVP of software engineering Craig Federighi who more or less confirmed his suspicions by saying that while Apple tries “to bring as many new software capabilities to as many devices as possible”, it isn’t always possible as is the case with the iPhone 6 and 6 Plus (and presumably devices older than that).
This doesn’t mean that Siri Shortcuts won’t work completely because as Trevisani points out, he was only asking about a specific feature of Siri Shortcuts, so like we said, we could simply be looking at limited functionality. Either way we’ll have to wait and see as iOS 12 doesn’t have a firm release date yet, but we should know more at Apple’s iPhone event which takes place on the 12th of September.