Fir Private Spaces now default to x86_64 architecture

Change effective on 21 August 2026

All new Fir-generation Private Spaces now default to x86_64 (Intel/AMD) architecture instead of ARM64 (Graviton). This change improves the developer experience by defaulting to the more widely used x86_64 architecture, and provides better compatibility with existing x86_64-based apps and dependencies.

What’s Changing:

  • New Fir Private Spaces created after August 21, 2026 use x86_64 architecture by default.
  • Apps in x86_64 spaces run on x86_64-based dynos.
  • Build processes automatically generate x86_64-compatible images.

What’s the Same:

  • Existing ARM-based Fir spaces continue to operate normally.
  • Apps inherit their architecture from their parent space.
  • You can’t have both x86_64 and ARM apps in the same space.

Action Required:

  • If you developed and tested your app on ARM architecture and you need a new space, contact support to request an ARM-based space.
  • When migrating apps between spaces, make sure the source and target spaces use the same architecture.