RHEL is EOLing CPU architectures that CERN still relies on heavily.

> RHEL 9 mandated x86-64-v2, requiring instruction sets like SSE4.2 and POPCNT, while RHEL 10 targets x86-64-v3. CERN's accelerator infrastructure manages more than 2,200 specialised front-end computers and 17,000 embedded devices, including legacy Core 2-era and custom industrial boards, engineered for 10- to 15-year lifecycles aligned with long-term accelerator shutdown windows. Upstream microarchitecture mandates threatened to abruptly obsolete thousands of functional, purpose-built control nodes.