DataStax Community Edition 2.1.7 and 2.0.16 are available for download from Planet Cassandra! These are maintenance releases of the 2.0 and 2.1 branches, neither of which have any version-specific upgrade notes, but do read through the all the relevant NEWS entries if you are upgrading from an older release.

DataStax Community Edition 2.1.7 CHANGES.txt and NEWS.txt

DataStax Community Edition 2.0.16 CHANGES.txt and NEWS.txt