Nightly builds of ProB 2 for Rodin 3 can be obtained from within Rodin using the update site http://nightly.cobra.cs.uni-duesseldorf.de/prob2/updates/nightly/. This version of ProB is deprecated. We recommend that you either use the standard plugin for Rodin (which still uses the old Java API) or use the new ProB2-UI based on JavaFX which can also directly load machines from Rodin workspaces.