The current version of the OPM Retrofitting tool can be applied to MBDs developed with Sybase and can be adapted straightforwardly to MBDs developed with other commercial relational DBMSs, such as Oracle and Informix. We are in the process of extending the OPM Retrofitting tool to MBDs developed using non-relational DBMSs, such as ACeDB, and/or defined using non-relational DDLs, such as ASN.1. These extensions will broaden the range of MBDs for which an OPM view can be constructed, and that can thus be included in an OPM multidatabase system.