Bold Reports® releases several major versions in a year. Each version includes new features, bug fixes and other improvements.
You can refer the features and enhancements from the Release Notes.
To upgrade the Bold Reports® Azure App Service to latest version you must have access rights to edit the Bold Reports® Server App Service.
Follow below steps to upgrade Bold Reports® Azure App Service version from v2.x to v2.4.19 .
App Services in Microsoft Azure Services.

Bold Reports Azure App Service.Overview section, Click the Stop button.

Deployment center in the left panel of the Bold Reports® App Service.

Disconnect. Now the deployment panel will open.

External in the source control tab and click the Continue.

App Service build service and click the Continue.

Configure tab and click the Continue.
https://github.com/boldreports/bold-reports-azure.gitv{release-version}GitNo
Finish option. The “Successfully set up deployment” notification will be shown in the notification.
11. Select the Sync button in the deployment center page.
12. Synchronization request submitted notification will be shown in the notification and synchronization progress is shown in the deployment center page.
13. Please wait until synchronization is completed.
14. Select App Service Editor in the left panel of the Bold Reports® Azure App Service, then click Go.
15. Copy your Web App URL, and then update the following xml node InternalAppReportUrl in the config.xml file under wwwroot/IDP/UMS/Configuration/boldreports/config.xml.
The URL must be, InternalAppReportUrl- {web App URL}/reporting
16. Copy your Web App URL, and then update the following xml node InternalAppDataServiceUrl and InternalAppIdpUrl in the config.xml file under wwwroot/Report Server/Configuration/config.xml.
The URL must be, InternalAppDataServiceUrl – {web App URL}/reporting/reportservice
InternalAppIdpUrl – {web App URL}/
17. Start the Bold Reports® Azure App Service by clicking Start button from Overview section.
18. Now, we have completed the Bold Reports® upgrade process. Launch the Bold Reports® by clicking the browse option or type in the Bold Reports® URL in the browser.

Data Migration is not required for upgrading Bold Reports® Azure App Service from v2.x to latest version