Undefined method `set_client_encoding' when connecting to Postgres

When database.yml contains `encoding: utf8` line connection fails with message:

    NoMethodError: undefined method `set_client_encoding' for #<ActiveRecord::ConnectionAdapters::PostgreSQLAdapter:0xf1c1798>
    from <...>/lib/arjdbc/postgresql/adapter.rb:26:in `configure_connection'

As I read from postgresql JDBC driver documentation (http://jdbc.postgresql.org/documentation/91/connect.html) - "The client_encoding setting is set by the driver and should not be altered."

So, encoding option should be ignored (maybe with a warning if it don't correspond to one selected by driver), am i right?