New Oracle Versions
The Oracle database team has done a number of interesting things as seen in
Release Schedule of Current Database Releases (Doc ID 742060.1)
Release 12.2: New releases will be annual and the version will be the last two digits of the release year. The release originally planned as 12.2.0.2 will now be release 18, and the release originally planned as 12.2.0.3 will be release 19. Releases 18 and 19 will be treated as under the umbrella of 12.2 for Lifetime Support purposes. The expectation is for Oracle Database 19 to be the last release ("long term support" release) for 12.2.
Also, it looks like they have released version 18 in the Cloud as of March, but it will not be available to on-premise customers until the second half of 2018.