The OPatch version is not applicable for current OUI version

Version:

Oracle WLS 12.1.2.0

Issue:

Opatch lsinventory returns error when opatch command is issued from 12.1.2.0 version of Weblogic. 

Error:

opatch lsinventory -jdk $JAVA_HOME

OPatch Version : 13.1.0.0.0

OUI  Version : 12.1.0.1.0

The OPatch version is not applicable for current OUI version.

Since OUI Version starts with 12.1, Please go to 'My Oracle Support' and get right OPatch 12.1.*.*.* based on patch 6880880, release version 12.1.0.0.0 and \appropriate platform.

OPatch failed with error code 19

Reason:

The Error was due to the mismatch in opatch version and the inventory version. A DB software of 12C version is also available in same server. In my case  MW_HOME environment variable is set and PATH is set to $MW_HOME/OPatch directory. But the ORACLE_HOME environment variable was still set to the DB Home. Because of that the opatch utility checked the inventory file which it got from the Oracle DB Home oraInst.loc and error out

Solution:

Set ORACLE_HOME to MW_HOME_PATH location and re invoke opatch. 

Still better to close the previous Unix session and open a new one to avoid reference to any variables set previously.

After the correct ORACLE_HOME setting the versions read as follows

OPatch version    : 13.1.0.0.0

OUI version       : 13.1.0.0.0

Note: The error can come also if the opatch version is old compared to the inventory version