Percona Server for MongoDB is an enhanced, open source, and highly-scalable database that is a fully-compatible, drop-in replacement for MongoDB 3.4 Community Edition. It supports MongoDB 3.4 protocols and drivers.
Percona Server for MongoDB extends Community Edition functionality by including the Percona Memory Engine storage engine, as well as several enterprise-grade features:
Also, it includes MongoRocks storage engine, which is now deprecated. Percona Server for MongoDB requires no changes to MongoDB applications or code.
This release is based on MongoDB 3.4.22 which has addressed CVE-2019-2386. In Percona Server for MongoDB 3.4.22-2.20, there are no additional improvements or new features on top of those upstream fixes.
Release notes are available in the official documentation.