The following 3.4 features persist data that earlier MongogDB versions
cannot correctly handle and require that
featureCompatibilityVersion
be set to "3.4"
:
Index version
v: 2
.v:2
indexes add support for collation and decimal data type. Earlier index versions support neither collation nor the decimal data type.If
featureCompatibilityVersion: "3.4"
, indexes created in MongoDB 3.4 default tov: 2
. Otherwise, new indexes default tov: 1
.