If you are upgrading to R:BASE 11 from R:BASE X/X.5 Enterprise (Version 10.x), you are only required to connect to the database in order to complete the conversion.
At this point in R:BASE use, R:BASE 11 and R:BASE X/X.5 Enterprise can connect to the same database. However, once any Version 11 specific features are implemented (such as static variables or database comments), R:BASE 10.x Enterprise versions can no longer connect to the database. A minor version number is stored within file 1 of the database files. R:BASE 11 will automatically alter the value if any new features of version 11 are implemented. Also, any new databases created in R:BASE 11 will start with the elevated minor version, and R:BASE 10.x Enterprise versions will not be able to connect to the database. To use the forms, reports, and labels in the same dual version environment, R:BASE 11 should not be used to alter and save the objects. Doing so will prevent the object from being recognized in the prior R:BASE version.
Please review the "What's New in R:BASE 11 for Windows" PDF document for the list of other new features.