added Ditto 2.1.0 announcement blogpost

Signed-off-by: Thomas Jaeckle <[email protected]>

Author: thjaeckle

documentation/src/main/resources/_posts/2021-09-27-release-announcement-210.md

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+---
+title: "Announcing Eclipse Ditto Release 2.1.0"
+published: true
+permalink: 2021-09-27-release-announcement-210.html
+layout: post
+author: thomas_jaeckle
+tags: [blog]
+hide_sidebar: true
+sidebar: false
+toc: false
+---
+
+The Eclipse Ditto teams announces availability of Eclipse Ditto [2.1.0](https://projects.eclipse.org/projects/iot.ditto/releases/2.1.0).
+
+As the first minor of the 2.x series it adds a lot of new features, the highlight surely being the full integration of
+[Apache Kafka as Ditto managed connection](connectivity-protocol-bindings-kafka2.html).
+
+
+## Adoption
+
+Companies are willing to show their adoption of Eclipse Ditto publicly: [https://iot.eclipse.org/adopters/?#iot.ditto](https://iot.eclipse.org/adopters/?#iot.ditto)
+
+From our various [feedback channels](feedback.html) we however know of more adoption.  
+If you are making use of Eclipse Ditto, it would be great to show this by adding your company name to that list of 
+known adopters.  
+In the end, that's one main way of measuring the success of the project.
+
+
+## Changelog
+
+The main improvements and additions of Ditto 2.1.0 are:
+
+* Support consuming messages from Apache Kafka -> completing the Apache Kafka integration as fully supported Ditto managed connection type
+* Conditional requests (updates + retrievals)
+* Enrichment of extra fields for ThingDeleted events
+* Support for using (HTTP) URLs in Thing and Feature "definition" fields, e.g. linking to WoT (Web of Things) Thing Models
+* HMAC based authentication for Ditto managed connections
+* SASL authentication for Azure IoT Hub
+* Publishing of connection opened/closed announcements
+* Addition of new "misconfigured" status category for managed connections indicating that e.g. credentials are wrong or connection to endpoint could not be established to to configuration problems
+* Support "at least once" delivery for policy subject expiry announcements
+
+The following notable fixes are included:
+
+* Fix "search-persisted" acknowledgement not working for thing deletion
+* Fix reconnect loop to MQTT brokers when using separate MQTT publisher client
+
+The following non-functional work is also included:
+
+* Support for tracing reporting traces to an "Open Telemetry" endpoint
+* Improving cluster failover and coordinated shutdown + rolling updates
+* Logging improvements, e.g. configuring a logstash server to send logs to or more options to configure a logging file appender
+* Improving background deletion of dangling DB journal entries / snapshots based on the current MongoDB load
+* Improving search update by applying "delta updates" saving lots of bandwidth to MongoDB
+* Reducing cluster communication for search updates using a smart cache
+
+Please have a look at the [2.1.0 release notes](release_notes_210.html) for a more detailed information on the release.
+
+
+## Artifacts
+
+The new Java artifacts have been published at the [Eclipse Maven repository](https://repo.eclipse.org/content/repositories/ditto/)
+as well as [Maven central](https://repo1.maven.org/maven2/org/eclipse/ditto/).
+
+The Ditto JavaScript client release was published on [npmjs.com](https://www.npmjs.com/~eclipse_ditto):
+* [@eclipse-ditto/ditto-javascript-client-dom](https://www.npmjs.com/package/@eclipse-ditto/ditto-javascript-client-dom)
+* [@eclipse-ditto/ditto-javascript-client-node](https://www.npmjs.com/package/@eclipse-ditto/ditto-javascript-client-node)
+
+
+The Docker images have been pushed to Docker Hub:
+* [eclipse/ditto-policies](https://hub.docker.com/r/eclipse/ditto-policies/)
+* [eclipse/ditto-things](https://hub.docker.com/r/eclipse/ditto-things/)
+* [eclipse/ditto-things-search](https://hub.docker.com/r/eclipse/ditto-things-search/)
+* [eclipse/ditto-gateway](https://hub.docker.com/r/eclipse/ditto-gateway/)
+* [eclipse/ditto-connectivity](https://hub.docker.com/r/eclipse/ditto-connectivity/)
+* [eclipse/ditto-concierge](https://hub.docker.com/r/eclipse/ditto-concierge/)
+
+<br/>
+<br/>
+{% include image.html file="ditto.svg" alt="Ditto" max-width=500 %}
+--<br/>
+The Eclipse Ditto team