Hi @MaheshP83, 

Here are some links and screenshots that could help your decision. 

• Java Versions supported by Pega 8.5-8.8  (as per the details, Java SE8 is deprecated & JAVA SE 11 & 17 are supported in Pega 8.8 ) 

• Referring to Notes on Java Virtual Machines (JVMs) section in the above link , it says "Tomcat does not bundle a JVM in its application. Pega recommends using either OpenJDK, Oracle, or IBM Java 8 or Java 11, at the Java vendor’s latest patch level (unless it is specifically stated that that patch level does not run with Pega Platform)." Highlighted the text for your quick ref. 

• Garbage collection and its arguments are different between Java 8 & 11. 

  • The garbage collection arguments in Java 8 and Java 11 differ in terms of the default garbage collector used. In Java 8, the default garbage collector is the Parallel collector, while in Java 11, it is the G1GC (Garbage-First Garbage Collector). Additionally, the way to enable GC logging also differs between the two versions.

  • In Java 8, you can enable GC logging using the following JVM arguments: -XX:+PrintGCDetails -XX:+PrintGCDateStamps -Xloggc:{file-path}, while in Java 11, you can use -Xlog:gc*:file={file-path}.

    The main difference between them is that the parallel collector runs multiple threads to speed up garbage collection. This difference in the default garbage collector and the method to enable GC logging can impact the performance and monitoring of the application's garbage collection process.

  • So, you may need to check the existing configuration and decide to update accordingly.

• You can check the details about the Hazelcast at this Link.

  • Hazelcast 5.x version supports the following Java versions:

    - Amazon Corretto 11 and 17

    - Azul Zulu 11 and later

    - Azul Zing 11

    - Oracle 11 and later

    - Red Hat build of OpenJDK 11

    - Microsoft Build of OpenJDK 11

    - IBM Semeru Runtime (OpenJ9) 11

    - AdoptOpenJDK 11

  • Hazelcast 5.x version no longer supports JDK 8 as a runtime. (Link :  https://docs.hazelcast.com/hazelcast/5.3/deploy/versioning-compatibility )

Based on the above information, while i couldnt find any resource / documentation saying issues with Java 8 in Pega 8.8, it looks more beneficial / futuristic considering Java version 11 for upgrade. 

Hope this information helps you. Please share your thoughts and findings (issues / any other resources) as we are also embarking on a similar upgrade path.