JavaServices in IS 601

Hi all,
Currently we are using IS 4.6,we are in the process of migrating to IS 6.0.1,I have a query regarding the migration process.What are the things to be considered regarding the java services,during the process of migration.Do i need to modify the Java Services which we have developed,in order to make them work in IS 6.0.1

TIA

It all depends of what you are doing in your services. The webMethods API is backwards compatible to 4.6 and code looks exactly the same. They even both run on JVM 1.3.x