Amazon RDS for PostgreSQL now supports PostgreSQL major version 10. PostgreSQL 10 includes various new features including native table partitioning, support for improved parallelism in query execution, ICU collation support, column group statistics, enhanced postgres_fdw extension, and many more. Additionally, this release includes an upgraded version of the PLV8 extension and will have huge pages enabled by default. 

Source: Amazon Web Services News PostgreSQL 10 now Supported in Amazon RDS