FairCom DB V12 and FairCom RTG V3 clients are not compatible with servers from prior releases due to this new support. Transaction logs created by a server without 4-byte file number support are incompatible with servers that use 4-byte file number support, and vice-versa. When this incompatibility is detected, the database engine fails to start up with error LFRM_ERR (666), "incompatible log format."
For more information, see Support opening more than 32,767 files.