<!-- wp:paragraph -->
<p>This morning MongoDB released v4.2 to the world!</p>
<!-- /wp:paragraph -->

<!-- wp:paragraph -->
<p>Key highlights of MongoDB 4.2 include:</p>
<!-- /wp:paragraph -->

<!-- wp:list -->
<ul><li><strong>Distributed Transactions</strong>&nbsp;extending MongoDB’s multi-document ACID guarantees from replica sets to sharded clusters, enabling you to serve an ever broader range of use cases. </li><li><strong>On-Demand Materialized Views</strong>&nbsp;using the new <code>$merge</code> operator. Caching the output of a large aggregation in a collection is a common pattern, and the  <code>$merge</code>  operator lets you update those results efficiently instead of completely recalculating them. Take a look&nbsp;<a href="https://www.mongodb.com/blog/post/coming-in-mongodb-42--ondemand-materialized-views">at this blog</a>&nbsp;to get started.</li><li><strong>Wildcard Indexes</strong>&nbsp;make it easy and natural to model highly heterogeneous collections like product catalogs, without sacrificing great index support. You simply define a filter that automatically indexes all matching fields, sub-documents, and arrays in a collection.&nbsp;<a href="https://www.youtube.com/watch?v=mUWZPdHopYs&amp;list=PL4RCxklHWZ9vG8ikkcCS94nxo0Td-Mm2s&amp;index=3">Watch the demo</a>&nbsp;to learn more.</li><li><strong>MongoDB Query Language enhancements</strong>&nbsp;such as more expressive updates, new math operators, and expanded regex support.&nbsp;<code>update</code>&nbsp;and&nbsp;<code>findAndModify</code>&nbsp;commands can now reference existing fields, and incorporate aggregation pipelines for even more expressivity. Check out&nbsp;<a href="https://www.mongodb.com/blog/post/coming-in-mongodb-42-pipeline-powered-updates-and-more-expressive-queries">this blog</a>&nbsp;to see examples of how all of this helps you write more powerful queries with less code.</li><li><strong>Retryable Reads and Writes</strong>, reducing the complexity of writing code that handles transient cluster failures.</li></ul>
<!-- /wp:list -->

<!-- wp:paragraph -->
<p><a href="https://www.mongodb.com/blog/post/mongodb-42-is-now-ga-ready-for-your-production-apps">https://www.mongodb.com/blog/post/mongodb-42-is-now-ga-ready-for-your-production-apps</a></p>
<!-- /wp:paragraph -->