While applying AMX BPM 4.2.0 HF 2, TCT wizard - "Upgrade TIBCO ActiveMatrix BPM Instance" can result in a failure if JRE 8 is not being used.

Symptoms - 
- TCT fails while starting AMX BPM product application (commonly known as amx.bpm.app). 
- Component - "WorkManager/extension.usertask" of amx.bpm.app is in START_FAILED status due to the following error - 

java.lang.UnsupportedClassVersionError: com/tibco/n2/ut/model/TypeType : Unsupported major.minor version 52.0

Cause - 
Component "WorkManager/extension.usertask" is compiled with Java 8 in 4.2.0 HF 2

While applying TIBCO ActiveMatrix BPM (AMX BPM) 4.2.0 hotfix (HF) 2, TIBCO Configuration Tool (TCT) wizard - "Upgrade TIBCO ActiveMatrix BPM Instance" can result in a failure if Java Runtime Environment (JRE) 8 is not being used.

All Supported Operating Systems

Apply 4.2.0 HF 2 on a AMX BPM environment which has been configured to use JRE 8. 

If upgrading from AMX BPM v3.1.0 or earlier, please update to JRE 8 prior to upgrading to 4.2 HF 2. 

Note: When using JRE 1.8 update 172 or higher, TIBCO ActiveMatrix platform 3.3.0 HF 23 needs to be applied and a JVM argument needs to be set. Below is the description of this closed issue from 3.3.0 HF 23 readme - 

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AMX-16650
Previously with JRE 1.8 update 172, TIBCO ActiveMatrix tibcohost failed to start with following error:
"java.security.UnrecoverableKeyException: Rejected by the jceks.key.serialFilter or jdk.serialFilter property"

This failure is now addressed with the addition of the property jceks.key.serialFilter. If the property is added to end of <TIBCO_HOME>/amx/3.3/scripts/rpflauncher_classpath_3.3.0.tra for all the <TIBCO_HOME>s 
within the enterprise as follows, the error is no longer seen.

java.property.jceks.key.serialFilter=com.tibco.**;java.lang.Enum;java.security.KeyRep;java.security.KeyRep$Type;javax.crypto.spec.SecretKeySpec;!*

The same property must be added to the end of <TIBCO_HOME>/tct/1.4/TIBCOConfigurationTool.ini when TIBCO Configure Tool (TCT)) is involved, that is:

-Djceks.key.serialFilter=com.tibco.**;java.lang.Enum;java.security.KeyRep;java.security.KeyRep$Type;javax.crypto.spec.SecretKeySpec;!*
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Support for JRE 8 for older AMX BPM versions - https://support.tibco.com/s/article/TIBCO-ActiveMatrix-BPM-versions-2-0-0-3-1-0-Support-for-Java-Runtime-Environment-JRE-1-8
JRE Updater Tool - https://docs.tibco.com/products/tibco-activematrix-updater-tool-for-java-runtime-environment-jre-1-1-0
JRE 8 update 172 issue - https://support.tibco.com/s/article/Node-startup-fails-with-new-JRE
AMX 3.3.0 HF 23 release announcement - https://support.tibco.com/s/article/Hotfix-TIB-amx-3-3-0-hotfix023-is-available-for-TIBCO-ActiveMatrix-R-BPM-2-2-0-4-2-0-and-TIBCO-Business-Studio-BPM-Edition-3-6-0-4-2-0