London court rejected Apple's appeal in its dispute with Optis, claiming that iPhone and iPad models infringed on 4G patents

The Court of Appeal in London found on Tuesday that Apple infringed on two telecommunications patents used in devices such as iPhones and iPads, dismissing the tech giant's appeal in a long-running battle with a US patent holder.

In 2019, Texas-based Optis Cellular Technology sued Apple over the usage of patents that Optis claims are critical to specific technical standards, such as 4G.

Last year, the High Court in London determined that two of Optis' 4G inventions were so-called standard essential patents, and that Apple had infringed on them.

In May, Apple filed an appeal against that ruling, claiming that the two patents at question were not crucial to 4G standards and that it had not infringed on them.

However, the Court of Appeal dismissed its case, with Judge Colin Birss writing in a written judgement that the High Court was "right to reject (Apple's) argument for non-infringement" and on the question of the patents being essential.

Apple and Optis did not reply quickly to requests for comment.

Tuesday's judgement is the latest in a legal struggle between Apple and Optis that began in 2019 and has resulted in six distinct trials and multiple appeal hearings in the United Kingdom alone.

Following a ruling in October that Optis is entitled to an injunction to stop Apple infringing its patents before a court has ruled on the fair, reasonable, and non-discriminatory terms of use, the Court of Appeal upheld an appeal by Optis last month against an earlier decision to revoke two other 4G-related patents.

Apple was granted permission to appeal the October verdict earlier this year.