Short format works fine 
IPv6-only server still running for almost a year now without problems.
Not using it for anything mission critical as of yet, as installing updates is a bit "exciting" trying to combine main repo with the experimental ipv6-repo (avoid overwriting ipv6-patched packages on update) but still getting CVE's fixed from kernel etc. Haven't broken anything yet (AFAIK) - just looking forward to see this in a release.
(+ There might be a few useful details hiding here: https://github.com/xcp-ng/xcp/issues/437 in case)
