Java Version 1.7.0_25 (51.0)
Java VM Name Java HotSpot(TM) 64-Bit Server VM
Java Build Info 23.25-b01, mixed mode
Java Vendor Oracle Corporation
Java Home C:\SoftwareAG95\jvm\jvm\jre
Java Entrust Toolkit Version Entrust Authority(TM) Security Toolkit for the Java(R) Platform version 8.0 Patch 179221 FIPS
Server Process Id 7252
Java Classpath C:\SoftwareAG95\common\lib\tw-3.5.20/wrapper.jar
C:/SoftwareAG95/profiles/IS/../../common/runtime/lib/runtime/platform-bootstrap.jar
C:\SoftwareAG95\common\runtime\agent\repository\plugins\org.eclipse.equinox.launcher_1.3.0.0000-0001.jar
IntegrationServer 9.5 is running on a JVM 1.7 by default wich does not understand Class File version 52, only version 51 and below.
CentraSite 9.12 is using JVM 1.8 by default.
You can try to update the JVM for your IS by applying the corresponding Fix for the Java-Package to your installation.
Can you explain how your installation is organized?
Are IntegrationServer 9.5 and CentraSite 9.12 sharing the same installation directory?
You can try to split these into two installation directories: one for IntegrationServer and one for CentraSite.
In this case IntegrationServer should continue to use the CentraSite 9.5 libraries which are suitable for JVM 1.7.