# Event messages

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This page was generated from content adapted from the [AWS Developer Guide](https://github.com/awsdocs/aws-iot-docs.git)
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## Lifecycle events

* **Note**\
  Lifecycle messages might be sent out of order. You might receive duplicate messages.
* **Note**\
  With AWS IoT Device Management fleet indexing, you can search for things, run aggregate queries, and create dynamic groups based on thing Connect/Disconnect events. For more information, see [Fleet indexing](https://docs.aws.amazon.com/iot/latest/developerguide/iot-indexing.html).
* **Note**\
  Lifecycle messages might be sent out of order. You might receive duplicate messages.