The number of digits is meaningful, and many shops use less digits to make distributed communications easy between instances on different sub releases using compatible=10.2.
Failure to standardize the compatible parameter can precipitate the following error:
ORA-23375: feature is incompatible with database version
You should set the compatible parameter to the version of Oracle that you are using in order to use all replication features of that version of the database.
Here is the mapping for the compatible parameter digits:
Oracle Database Release Default Value Minimum Value Maximum Value
Oracle8i release 8.1.7 8.0.0 8.0.0.0.0 8.1.7.x.x
Oracle9i release 9.0.1 8.1.0 8.1.0.0.0 9.0.1.x.x
Oracle9i release 9.2 8.1.0 8.1.0.0.0 9.2.0.x.x
Oracle Database 10g release 10.1 10.0.0 9.2.0.0.0 10.1.0.x.x
Oracle Database 10g release 10.2 10.2.0 9.2.0.0.0 10.2.0.x.x
Oracle 11g Release 11.1 11.0.0 10.0.0.0.0 11.1.0.x.x
Oracle 11g Release 11.2 11.0.0 10.0.0.0.0 11.2.0.x.x
