ODS 52 is the default ODS level

The default On-Disk Structure (ODS) for databases is now ODS 52, the ODS for IBM Domino and Notes 9.0.1. Unless there is a Create_Rx_Databases=1 notes.ini setting on server or client that specifies another ODS (for example, Create_R10_Databases=1), ODS 52 is automatically used with new databases or databases that are compacted using copy-style compacting.