It is possible to accidentally mix different versions of Spring JARs when using Maven.
For example, you may find that a third-party library, or another Spring project, pulls in a transitive dependency to an older release. If you forget to explicitly declare a direct dependency yourself, all sorts of unexpected issues can arise.
To overcome such problems Maven supports the concept of a “bill of materials” (BOM) dependency. You can import the spring-framework-bom in your dependencyManagement section to ensure that all spring dependencies (both direct and transitive) are at the same version.