Below recommendation is from the Spring Framework lead Juergen Hoeller
To a large degree, an upgrade from Spring Framework 3.2 (or earlier) to 4.0.1 should be as straightforward as a change of version numbers in your Maven POMs. Note that you may have to upgrade specific third-party dependencies to a recent enough version (e.g. Hibernate 3.6+, Quartz 1.8+, Jackson 1.8+, Tiles 2.2+), but other than that, you should be able to get all the benefits of the Spring 4 line with hopefully very little effort.
I hope this holds good for other versions as well.