Masimo, the medical technology company whose lawsuit led to the temporary sales pause of the Apple Watch Series 9 and Ultra 2, has sued the US Customs and Border Protection days after Apple released its redesigned blood oxygen monitoring feature. This is just the latest update in the lengthy legal saga between Masimo and Apple, which started when the former sued the iPhonemaker in 2021, accusing it of infringing on several of its light-based blood oxygen monitoring patents. After a court sided with Masimo in 2023, Apple was forced to stop selling the Watch Series 9 and the Ultra 2 in the US for a few weeks. In order to circumvent the import ban for the devices, Apple removed the Blood Oxygen app for the watch models sold in the US. Just a few days ago, however, the company introduced a "redesigned Blood Oxygen feature" for the Watch Series 9, Series 10 and Watch Ultra 2 models. The feature works by measuring and calculating data from the watches' sensors on their paired iPhones instead.