I'm currently upgrading from Struts 2.0.14 to 2.1.6. I have existing Struts 1.X in place as well as AJAX. My AJAX is on a page which is almost exclusively Struts 1 and was working fine with 2.0.14, but now I'm getting the "There is no Action mapped for namespace / and action name populateSelect" error. I'm not exactly sure what I need to map. I'm also wondering if this is going to mean I need to change my JSPs wherever I'm using AJAX. Can somebody point me in the right direction? Please let me know if I can provide any more information that would clarify my predicament?