Modify Java Code to work on Tomcat 7 to 9

Hi, we have a web portal that is in Java / J2EE / MySQL / Struts / running under Tomcat 7. We recently upgraded the Tomcat to V9. We are looking for someone who can make the necessary changes to the code so that it would run in Tomcat 9. The code is developed in Java v8 and Servlet version later than 4.0. Those who have done this type of work, please apply. Thank you.