# production build issue with `date-fns`
Preview failing after upgrading to Nuxt 4
pending triagenitroneeds reproduction
Nuxt Build Error on VERCEL [error] [nuxt] [request error] [unhandled] [500] [nuxt] instance unavailable nuxt
3.xpending triageneeds reproduction
Preview mode broken after upgrade to v4
pending triagepossible regression
Nuxt 2.15.8 modern build issues on IE11/Edge (function* unescaped)
pending triage2.xneeds reproduction