Directory Server 11g Release 1 (11.1.1) supports an unlimited number of masters in a multi-master topology. This and other changes might mean that you redesign your topology rather than migrate to an identical topology with new servers. See Part III, Logical Design, in Oracle Fusion Middleware Deployment Planning Guide for Oracle Directory Server Enterprise Edition before continuing.
When migrating replicated old server instances, you typically start with the consumers, continue with the hubs, and finish with the masters. This bottom-up approach involves interrupting only one server at a time, rather than interrupting an entire branch of the replication topology. The approach also helps you avoid potential custom schema synchronization issues between masters and consumers.
In a Multi-Master Replication configuration that includes 5.2 servers, a maximum of four masters (of any version) is supported due to the four master restriction with version 5.2. Therefore, as long as your topology includes any 5.2 servers, the topology cannot have more than four masters.