> The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version.
## Modules to Import
```
import deviceInfo from '@ohos.deviceInfo'
```
## System Capabilities<a name="section373mcpsimp"></a>
<tdclass="cellrowborder"valign="top"width="50.664933506649334%"headers="mcps1.1.6.1.5 "><pid="p77481025142412"><aname="p77481025142412"></a><aname="p77481025142412"></a>Device serial number.</p>
<tdclass="cellrowborder"valign="top"width="50.664933506649334%"headers="mcps1.1.6.1.5 "><pid="p1632411093512"><aname="p1632411093512"></a><aname="p1632411093512"></a>Release type. The options are as follows:</p>
<aname="ul143244108350"></a><aname="ul143244108350"></a><ulid="ul143244108350"><li>Canary: Preliminary release open only to specific developers. This release does not promise API stability and may require tolerance of instability.</li><li>Beta: Release open to all developers. This release does not promise API stability and may require tolerance of instability.</li><li>Release: Official release open to all developers. This release promises that all APIs are stable.</li></ul>
<tdclass="cellrowborder"valign="top"width="50.664933506649334%"headers="mcps1.1.6.1.5 "><pid="p9345223244"><aname="p9345223244"></a><aname="p9345223244"></a>Major version, incrementing along with OS version updates.</p>
<tdclass="cellrowborder"valign="top"width="50.664933506649334%"headers="mcps1.1.6.1.5 "><pid="p49961762616"><aname="p49961762616"></a><aname="p49961762616"></a>Senior version, incrementing along with architecture and feature updates.</p>
<tdclass="cellrowborder"valign="top"width="50.664933506649334%"headers="mcps1.1.6.1.5 "><pid="p761314532413"><aname="p761314532413"></a><aname="p761314532413"></a>SDK API version.</p>
<tdclass="cellrowborder"valign="top"width="50.664933506649334%"headers="mcps1.1.6.1.5 "><pid="p68311418266"><aname="p68311418266"></a><aname="p68311418266"></a>First API version.</p>
| osReleaseType | string | Yes| No| OS release type. The options are as follows:<br>- **Canary**: Preliminary release open only to specific developers. This release does not promise API stability and may require tolerance of instability.<br>- **Beta**: Release open to all developers. This release does not promise API stability and may require tolerance of instability.<br>- **Release**: Official release open to all developers. This release promises that all APIs are stable.|
| osFullName | string | Yes| No| OS version.|
| majorVersion | number | Yes| No| Major version, incrementing along with OS version updates.|
| seniorVersion | number | Yes| No| Senior version, incrementing along with architecture and feature updates.|
| featureVersion | number | Yes| No| Feature version.|
| buildVersion | number | Yes| No| Build version.|
| sdkApiVersion | number | Yes| No| SDK API version.|
| firstApiVersion | number | Yes| No| First API version.|
> - The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - This is a system API and cannot be called by third-party applications.
<tdclass="cellrowborder"valign="top"width="67.35%"headers="mcps1.1.5.1.4 "><pid="p175228526455"><aname="p175228526455"></a><aname="p175228526455"></a>Key of the system attribute</p>
<tdclass="cellrowborder"valign="top"width="83.54%"headers="mcps1.1.3.1.2 "><pid="p026955154811"><aname="p026955154811"></a><aname="p026955154811"></a>System attribute value. If the specified key does not exist, the default value is returned. If no default value has been set, an empty string will be returned.</p>
</td>
</tr>
</tbody>
</table>
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the system attribute.|
| def | string | No| Default Value|
**Return value**
| Type| Description|
| -------- | -------- |
| string | System attribute value. If the specified key does not exist, the default value is returned. If no default value has been set, an empty string will be returned.|
<tdclass="cellrowborder"valign="top"width="63.28407867697427%"headers="mcps1.1.5.1.4 "><pid="p8656111544920"><aname="p8656111544920"></a><aname="p8656111544920"></a>Key of the system attribute</p>
<tdclass="cellrowborder"valign="top"width="61.99%"headers="mcps1.1.5.1.4 "><pid="p645454720398"><aname="p645454720398"></a><aname="p645454720398"></a>Key of the system attribute</p>
<tdclass="cellrowborder"valign="top"width="67.35%"headers="mcps1.1.5.1.4 "><pid="p4289142812409"><aname="p4289142812409"></a><aname="p4289142812409"></a>Key of the system attribute</p>
<tdclass="cellrowborder"valign="top"width="83.54%"headers="mcps1.1.3.1.2 "><pid="p2644115664211"><aname="p2644115664211"></a><aname="p2644115664211"></a>Promise, which is used to obtain the result asynchronously</p>
</td>
</tr>
</tbody>
</table>
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the system attribute.|
| def | string | No| Default Value|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise<string> | Promise used to return the execution result.|
<tdclass="cellrowborder"valign="top"width="67.35%"headers="mcps1.1.5.1.4 "><pid="p531161819498"><aname="p531161819498"></a><aname="p531161819498"></a>Key of the system attribute</p>
<tdclass="cellrowborder"valign="top"width="67.35%"headers="mcps1.1.5.1.4 "><pid="p141301747155214"><aname="p141301747155214"></a><aname="p141301747155214"></a>System attribute value to set</p>
</td>
</tr>
</tbody>
</table>
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the system attribute.|
| value | string | Yes| System attribute value to set.|
<tdclass="cellrowborder"valign="top"width="65.61769290724864%"headers="mcps1.1.5.1.4 "><pid="p27711349121916"><aname="p27711349121916"></a><aname="p27711349121916"></a>Key of the system attribute</p>
<tdclass="cellrowborder"valign="top"width="67.35%"headers="mcps1.1.5.1.4 "><pid="p13773849191918"><aname="p13773849191918"></a><aname="p13773849191918"></a>Key of the system attribute</p>
<tdclass="cellrowborder"valign="top"width="83.54%"headers="mcps1.1.3.1.2 "><pid="p4774164916199"><aname="p4774164916199"></a><aname="p4774164916199"></a>Promise, which is used to obtain the result asynchronously</p>
</td>
</tr>
</tbody>
</table>
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the system attribute.|
| def | string | No| Default Value|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise<string> | Promise used to return the execution result.|
