The most significant new features introduced in MongoDB 4.x include the following:
- Multidocument ACID transaction support
- Nonblocking secondary replica reads
- In-progress index build interruption
Transactions, secondary replica reads, and the aggregation pipeline are covered in detail in later chapters of this book. For an excellent brief overview of the major changes from MongoDB 3 to 4, go to
https://www.mongodb.com/blog/post/mongodb-40-release-candidate-0-has-landed.
https://www.mongodb.com/blog/post/mongodb-40-release-candidate-0-has-landed.
