# Understanding Data Privacy and Validity of a Sensor in Cumulocity IoT **URL:** \ **Category:** Knowledge Base\ **Tags:** cumulocity\ **Created:** [September 5, 2023, 9:59am UTC](https://community.cumulocity.com/t/understanding-data-privacy-and-validity-of-a-sensor-in-cumulocity-iot/3955 "2023-09-05T09:59:22Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Community-admin](https://dub1.discourse-cdn.com/flex005/user_avatar/community.cumulocity.com/community-admin/32/23712_2.png) [@Community-admin](https://community.cumulocity.com/u/Community-admin)\ **Post date:** [September 5, 2023, 9:59am UTC](https://community.cumulocity.com/t/understanding-data-privacy-and-validity-of-a-sensor-in-cumulocity-iot/3955/1 "2023-09-05T09:59:22Z")
## Introduction Data privacy and the validity of a sensor in Cumulocity IoT are important concerns for businesses that use the platform. Here, we answer some of the most common questions regarding this topic. ## Is there an upper limit on the storage of historical sensor data on the Cumulocity IoT platform? The answer to this question is that it depends on the retention rules defined for the tenant. For more details on retention rules, you can refer to the relevant documentation: > **[Cumulocity documentation](https://cumulocity.com/docs/)** > > This documentation offers comprehensive information on the Cumulocity platform both from a user and from a developer perspective. It reflects the latest state of the Cumulocity platform and is continuously updated to align with recent software... ## What happens to sensor data when a sensor device is removed from the Cumulocity IoT platform? If a device is deleted, corresponding data will immediately be deleted, and any unlinked data will be removed by cleanup activity, which is an internal activity triggered by the device delete action. To prevent the loss of data, an alternative to deleting a device is to arrange all retired devices in one group, which ensures that all reports remain correct. For more information on grouping devices, you can refer to [Assign inventory roles to device groups using the API](https://community.cumulocity.com/t/assign-inventory-roles-to-device-groups-using-the-api/7750)) . To prevent alarms from being raised for retired devices, disable connection monitoring. > Note: Deleting a device does not delete the data of its child devices. ## Will unregistering a smartphone from the Cumulocity IoT tenant or logging out of the platform affect the device registration status? Unregistering a smartphone from the Cumulocity IoT tenant will stop it from sending sensor values, but historical values will still be stored. User logout will not have any effect on device registration status. ## Relevant articles: > [@Cumulocity IoT - Connecting your smartphone](https://community.cumulocity.com/t/cumulocity-iot-connecting-your-smartphone/1760): > > Cumulocity IoT offers a free mobile application.The app is designed to collect measurements from your smartphone, nearby Bluetooth device sensors, and vehicle On-board Debug (OBD) sensors, and send them to your tenant on the Cumulocity IoT platform To register your smartphone, follow these steps: Download Cumulocity IoT Sensor App here: [Google App Store](https://play.google.com/store/apps/details?id=com.softwareag.cumulocity.iotcloudsensor) or [Apple App Store](https://apps.apple.com/us/app/id1516838930) as per your device type To Connect your smartphone with your tenant you have two options Option 1: QR code scan- If yo… ---
**Author:** ![Alexander\_Pester](https://dub1.discourse-cdn.com/flex005/user_avatar/community.cumulocity.com/alexander_pester/32/5725_2.png) [@Alexander\_Pester](https://community.cumulocity.com/u/Alexander_Pester)\ **Post date:** [September 6, 2023, 5:22am UTC](https://community.cumulocity.com/t/understanding-data-privacy-and-validity-of-a-sensor-in-cumulocity-iot/3955/2 "2023-09-06T05:22:46Z")
This addresses the device life-cylce from provisioning (onboarding), installation on site, production, maintenance and offboarding. There are of course different states from customer to customer. However, I which the Cumulocity IoT would provide such a device life-cycle state machine which is configurable, instead of addressing this in a such very technical way.