It is a specific process, usually handled by an upgrade guide.
So you’ll have to wait for /e/ team to publish a new release (or ask for it with a Gitlab issue).
Meanwhile, please refrain updating your selfhosted by your own, you may break the official upgrade process.
Good news for you, a new release is on it’s way 
: https://gitlab.e.foundation/e/infra/ecloud-selfhosting/-/merge_requests/95.
You’ll have to wait until it’s been tested, committed, approved …