There is currently no regression test of the OSGi manifests of the Spring framework bundles. So it is possible to introduce manifest changes which will prevent Spring framework being used as a drop-in upgrade for earlier versions of Spring. See
SPR-8788 for an example of this, which was caught relatively late in the day.
The suggested improvement is to introduce a nightly regression test of the ability to resolve Spring framework with a fixed basic set of non-optional dependencies. The test should probably fire up an OSGi framework such as Eclipse Equinox and install the Spring framework bundles and their non-optional dependencies. After this, the Spring framework bundles should be started and then the test should check that all of those bundles are in ACTIVE state.