One (user) can always change what ever he pleases, as long as it works. :-)
e.g. in my pre-JBoss days I used to run a popular energy portal app all based on JBoss trunk versions
(AS4.0.x, EJB3, Hibernate3, Portal2.0.x, ...)
Check the documentation (readme file, etc.) for the component. Often there is an ant script that will replace that component in a particular version of JBoss AS, and the docs will tell you that. As an example, from the various updates of Web Services I have looked at there were instructions for upgrading 4.2.x and 5.x.
Ales Justin: He he he. My question was more related to the complexity and mechanisms of the update process than to the possibility itself (because of the dependencies). Because I guess that it's not a matter of exchanging a few JARs only. Peter says that there are ant scripts to achieve that, so that's great. Thanks too .
Peter Johnson: Really interesting! I'll take a look to such files. This might avoid me many head aches soon. Thank you a lot .