I fetched error while tried to restore sample dhis2 database from (https://s3-eu-west-1.amazonaws.com/databases.dhis2.org/sierra-leone/2.31/2.31.0/dhis2-db-sierra-leone.sql.gz) into postgres 11.
It was giving error
psql:<>: invalid command \N
My working environment was,
OS: windows 10
Later I downgrade my database version to postgres 10 and everything worked fine and smooth.
This information might be helpful for whom who might want to work on dhis2 with postgres 11.