Library version choosing of cabal sandbox build

Hi, if I'm having a cabal file without an upper bound for a library, the newest available version of the library is 3, there's a local/user installation of the version 2 of the library, which version of the library is a cabal sandbox build supposed to use? In my case I can see that version 2 of the library is used. If this is intended, how can I ensure that always the newest version is used independent of any local/user installations? Thanks! Greetings, Daniel