What comes after openSUSE Leap 42.3 for SUSE's community non-rolling distribution? Version 15.
Richard Brown announced on the behalf of the openSUSE Board and Leap Release Manager that the next version after openSUSE Leap 42.3 will be openSUSE Leap 15. Yes, that's after pre-42 was openSUSE 13.2.
Also: Mailinglist Archive: opensuse-project (15 mails)