There are no special instructions for upgrading to 2.6.0. Check the Release Notes for the contents of the release.
Please consult the security advisories GHSA-f82x-m585-gj24 (moderate) and GHSA-v7fv-g69g-x7p2 (high) to see what security issues were fixed in this release. These will be published and become visible at January 18th, 2022.