engine
Version number of the cache engine to be used for the cache clusters in this replication group. If the version is 6 or higher, the major and minor version can be set, e.g., 6.2, or the minor version can be unspecified which will use the latest version at creation time, e.g., 6.x. Otherwise, specify the full version desired, e.g., 5.0.6. The actual engine version used is returned in the attribute engine_version_actual, see Attributes Reference below.