The iOS 12.1 update is now rolling out to all supported iOS 12 devices. You can install the update on your iPhone directly by going to Settings » General » Software Update section or you can manually download and install the iOS 12.1 update via iTunes using the IPSW firmware files.

The iOS 12.1 update comes with build number 16B93 for the iPhone XR, and 16B93 for the rest of the iPhone models.

Download iOS 12.1 IPSW firmware

iPhone and iPad modelsiOS versionDownload link
iPhone XS MaxiOS 12.1 (16B92)Download
iPhone XSiOS 12.1 (16B92)Download
iPhone XRiOS 12.1 (16B93)Download
iPhone XiOS 12.1 (16B92)Download
iPhone 8iOS 12.1 (16B92)Download
iPhone 8 PlusiOS 12.1 (16B92)Download
iPhone 7iOS 12.1 (16B92)Download
iPhone 7 Plus
iOS 12.1 (16B92)Download
iPhone SEiOS 12.1 (16B92)Download
iPhone 6siOS 12.1 (16B92)Download
iPhone 6s PlusiOS 12.1 (16B92)Download
iPhone 6iOS 12.1 (16B92)Download
iPhone 6 PlusiOS 12.1 (16B92)Download
iPhone 5siOS 12.1 (16B92)Download

For help installing iOS 12.1 through IPSW firmware file, follow our step-by-step guide at the link below:

How to install iOS IPSW firmware file using iTunes on Windows and Mac