See February 24, 2025:  NVD Technical Update on https://www.nist.gov/itl/nvd

NVD plans to (finally) retire the legacy JSON feeds and replace them with the 2.0 API (already exists) or 2.0 JSON files.

Once out, they say the 1.1 JSON files will stick around for another 3 months, so it's a ticking clock with an unknown start time