This documentation is for a version that has reached its End Of Life. Such versions are no longer supported and don't receive security updates. Consider updating to a newer version.
From 2.5¶
This update procedure applies if you are using v2.5.
Go through the following steps to update to the v3.3 LTS (v3.3.40).
Afterwards, it is strongly recommended to also update to the latest v4.6 LTS.