We have upgraded the Rule and data schema successfully now facing the issue when deploying the new prweb.ear file as part of the post-processing. 

Error Message - 

{"WFLYCTL0062: Composite operation failed and was rolled back. Steps that failed:" => {"Operation step-2" => {"WFLYCTL0080: Failed services" => {"jboss.deployment.unit.\"prweb.war\".undertow-deployment" => "java.lang.RuntimeException: java.lang.RuntimeException: Problem during method invocation (contextInitialized)

    Caused by: java.lang.RuntimeException: java.lang.RuntimeException: Problem during method invocation (contextInitialized)

    Caused by: java.lang.RuntimeException: Problem during method invocation (contextInitialized)

    Caused by: java.lang.RuntimeException: PRAppLoader was not properly initialized, unable to load class com.pega.pegarules.web.servlet.WebAppLifeCycleListener"}}}}

The approach followed is an out-of-place upgrade with a single migration and find the below env details -

Current Version: Pega v8.1.2 New Version: Pega v8.5.3 Application Server: JBOSS 7.2 Database: Oracle 12C

Updated rule schema details in the standalone.xml file and the DB connectivity is working fine.  Please share your experience or guideline, it can resolve the issue. thanks in advance!