I have finally received some additional information on this topic. Here is a message from our exam developers:
To prepare for the OCM exam, candidates should focus on mastering the tasks for each Skillset. Software can be downloaded from the Oracle Technology Network (OTN) to build a practice environment. Use the latest software available from OTN; it is not necessary to build a practice environment on the exact OS and database software versions used in the OCM exam. Later releases of Oracle server support nearly all features and functions of earlier ones; for any software version, relevant parameter values, naming differences and obsolete features may be found in the product documentation, which is available from OTN.
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