Final answer:
Alice v. CLS Bank case most severely limited software patentability.
Step-by-step explanation:
The court case that most severely limited software patentability is Alice v. CLS Bank.
Alice v. CLS Bank was a landmark case decided by the Supreme Court of the United States in 2014. It established a test for determining the patent eligibility of software inventions. The Court held that abstract ideas implemented on a generic computer are not eligible for patent protection.
This case had a significant impact on the software industry, as it made it more difficult to obtain patents for software-related inventions and clarified the boundaries of patent eligibility.