Issue
Router 2.0 is the Common Runtime router. Router 2.0 became GA in November 2024 and introduced several performance and security improvements, including HTTP/2 support and keepalives to dynos.
Below is the migration timeline and changelog for Router 2.0, maintained here for posterity.
Resolution
Migration Timeline
Heroku followed the below timeline for Router 2.0 migrations.
The week of February 3, 2025, the Heroku platform began migrating Eco-tier Common Runtime applications from the legacy router to Router 2.0.
The week of May 5, 2025, the Heroku platform began migrating Basic-tier Common Runtime applications to Router 2.0.
The week of July 10, 2025, the Heroku platform began migrating Standard & Performance-tier Common Runtime applications to Router 2.0.
On July 22, 2025, the Heroku platform paused the Router 2.0 migration in response to Incident 2863.
The week of September 8, 2025, the Heroku platform resumed migrating Standard & Performance-tier Common Runtime applications to Router 2.0.
Heroku Legacy router became end-of-life on September 30, 2025.
Changelog
The below Changelog items detail the history of the Router 2.0 release and automatic migration:
- November 21, 2024 - Router 2.0 is now generally available
- February 6, 2025 - Legacy Router end-of-life migration beginning for Heroku Eco-tier applications
- March 20, 2025 - Router 2.0 is now the default for all new Eco-tier Applications
- March 28, 2025 - Eco-tier applications now require Router 2.0
- July 1, 2025 - New Common Runtime applications now default to Router 2.0
- July 7, 2025 - Basic-tier applications now require Router 2.0
- July 10, 2025 - Standard and Performance-tier apps begin migrating to Router 2.0
- August 11, 2025 Router 2.0 migration resumes on September 8, 2025
- September 24, 2025 Standard and Performance-tier apps now require Router 2.0