If the reimport does not work (i.e. doesn't remove old versions of dependencies after a pom update), there is one more chance:
- open the project settings (CTRL+SHIFT+ALT+S)
- on modules, delete all libs that you want to reimport (e.g. duplicates)
- IDEA will warn that some are still used, confirm
- Apply and select OK
- then reimport all maven projects.