DP groups are enabled in 4.8 as part of https://github.com/openshift/ovn-kubernetes/pull/440, specifically https://github.com/openshift/ovn-kubernetes/pull/440/commits/7e7710240c399d4a55dffd1d4a3ef52df06d5489
Verified this bug on 4.8.0-0.nightly-2021-03-18-000857 # ovn-sbctl list logical_dp_group | wc -l 236
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: OpenShift Container Platform 4.8.2 bug fix and security update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2021:2438