Oracle RU and RUR

Starting with Oracle Database 18c, Oracle provides quarterly updates in the form of Release Updates (RU) and Release Update Revisions (RUR). Oracle no longer releases patch sets. 

In 12.2 in prior:
There used to be PSU and BP

Patch Set Update (PSU) 

contains usually security fixes and regression fixes, i.e. bug fixes.

Bundle Patch (BP) 

A superset of a PSU containing the PSU but optimizer fixes and functional fixes which may be sometimes feature extensions as well.

PSUs and BPs, each are cumulative. 

You’ll get the fixes from all previous PSUs or BPs for the same release included as well. 

Oracle 18.1 and higher:

Release Updates (RU) 
Release Update Revisions (RUR).

Release Updates (RU) 

These are parallel to BP
Oracle's quarterly Updates contain fixes for the bugs that customers are most likely to encounter

RUs are cumulative.

RUR - Release Update Revisions

RUR are being issued on the same quarterly basis to augment the RUs with fixes for known regressions and to include the latest security vulnerability fixes as well.

How to search:

In oracle Support:

Patch Search ->

Select Release ->

Select Platform ->

Select Description; Start With: DATABASE RELEASE