Kernel Version Upgrade in Progress

Change effective on 03 November 2023

Heroku is upgrading the Linux kernel powering dynos on both Common Runtime and in Private Spaces. This is a non-breaking change and no customer action is required to receive the upgrade.

The updated kernel has new features and system calls such as io_uring and epoll_pwait2 that may unlock performance improvements for some apps. See the roadmap for more discussion.

Once all Heroku apps are upgraded an additional changelog entry will be published and this changelog entry will be updated.

[4/2024 Update] – As of March 31, 2024, all Heroku apps are now upgraded and running on the latest Linux kernel version. This changelog formally indicates that the upgrade is complete.