I colleague of mine suggested applying the following 3 patches on top of 188.8.131.52
-Oracle JAVA SE home - see http://www.oracle.com/technetwork/topics/security/javacpujun2013-1899847.html
-Base Platform Fusion Middleware home PSU 184.108.40.206.6 Patch 17071664
-Oracle Database Management Plug-in home Unix: BP Patch 17366505
I am hoping to get some comments from the experts as to whether or not these are really required.
You can review below MOS note which documents the Oracle Recommended Patches in OEM,
Oracle Recommended Patches (PSU) for Enterprise Manager Base Platform (All Releases) (Doc ID 822485.1)
The note suggests recommended patches for different versions of OEM. PSU 4 on top of 220.127.116.11 is the latest PSU as of now.
As per my knowledge there no PSU released for 18.104.22.168. The note will be updated when PSU for 22.214.171.124 OMS will be released.
However, you can review the Bundle Patch information in below notes once which should meet your requirement,
Enterprise Manager 126.96.36.199 Bundle Patch Master Note (Doc ID 1572022.1)
Enterprise Manager Base Platform Management Agent 12cR3 Bundle Patch Bug List (Doc ID 1580355.1)
I hope this helps.