https://www.chromium.org/chromium-os/chromiumos-design-docs/chromium-os-kernel#TOC-Upgrades says:

> The kernel will be upgraded to a new version as soon as practical after a new version of the upstream kernel is released. [...] In practice, this will happen approximately every 3-6 months, and approximately every other kernel versions from upstream.

This policy is severely out of date and hasn't been practiced in 5+ years. It has gained new public interest with the Crostini launch (which is restricted mostly by kernel version), with users feeling cheated because we're not delivering the update cadence our documentation promised. It seems to be one of those few cases where outdated documentation really is worse than no documentation, so we should probably update or at least remove it.