In https://lists.oasis-open.org/archives/docbook-comment/201810/msg00000.html, Bob Stayton, TC Chair reports: 

Subject: The DocBook Schema v5.0.1 public review ended with no comments

From: Bob Stayton <bobs@sagehill.net>
To: docbook-comment@lists.oasis-open.org
Date: Wed, 31 Oct 2018 13:35:29 -0700

The public review for The DocBook Schema Version 5.0.1 Committee Specification Public Review Draft 01 announced in https://lists.oasis-open.org/archives/docbook-comment/201809/msg00000.html closed on 20 October 2018. The TC received no comments.