For the EJB modules I don't know, but you can put in web modules responding to an earlier version of the spec because those are fully backwards compatible. But why would you? The only thing you need to do is change a single line in the header of the web.xml for the webcomponent to bring it up to date (and maybe change the way you define your JSTL descriptor if you're using a really old version now).
What a stench! Central nervous system shutting down. Save yourself tiny ad!
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