V5R4 is the final release in which IBM will support Tomcat. IBM recommends that when it withdraws support that you get the open-source version of Tomcat at http://jakarta.apache.org or use WAS Express.
in V6R1 the Integrated Web Application Server is an alternative for IBM-supported ASF-Tomcat, previously shipped with HTTP Server for i5/OS. in V6R1 it is recommended that you migrate ASF Tomcat configurations to the Integrated Web application Server environment.
V6R1 is the first release to include an Integrated Web application server, an easy-to-configure and use Web container that does not require the installation of any other components. In concert with the 32-bit IBM Technology for Java JVM (used by default), this server gives you a consumable and efficient on-ramp to the Web. This support is also available via a latest PTF SF99114 on i5/OS V5R4.