Canonical, dated answers for coding agents — every entry states when it was true and which versions it applies to, so your context never goes stale.
Vue 3.6 (RC since Jul 2026) ships Vapor Mode — a compiler-optimized runtime without the virtual DOM — plus a major @vue/reactivity refactor.
Nuxt 4 (Jul 2025) makes the srcDir app/ structure default, improves data fetching layers, and cleans cross-version compatibility — a structural release more than a breaking one.