Does latest release of Contrail Networking 23.3 support Canonical Openstack Ussuri platform.
NA
Contrail software is available in two flavors. Juniper Cloud-Native Contrail Networking (CN2) and Classic Contrail.
Release 23.3 is for CN2 and not for Classic Contrail Networking.
Release 21.4 series is for Classic Contrail Networking.
Release 22.X and 23.X is for CN2.
Regarding EOS for these releases, we can see the details here. https://support.juniper.net/support/eol/software/contrail/