Publishing a Code-Customized Base Application for Business Central On-Prem

APPLIES TO: Business Central 2019 release wave 2 and later

This topic describes the steps and development environment configuration settings that are needed in order to customize the Base Application code in Dynamics 365 Business Central on-premises and publish the code-customized Base Application to the local server.


Instead of code-customizing the Base Application, it is strongly recommended to create extensions whenever possible.


The steps in this topic are not validated against a Docker environment. If you are running the on-premises installation and development from Docker, there can be dependencies and other steps that you need to take into consideration.


Make sure to have the following prerequisites installed to be able to follow the steps in this topic.

  • Dynamics 365 Business Central on-premises with the AL Language Development Environment option installed
  • Visual Studio Code
  • The AL Language extension

To publish a code customization for Business Central on-premises

  1. Get the Base Application source from the /Applications/BaseApp/Source folder on the DVD.

  2. Unzip the file and open the source folder in Visual Studio Code. This folder contains all of the base application objects and an app.json file with the settings enabled for OnPrem.

  3. Now, you must configure your launch.json file settings to the local server. For more information, see JSON Files.

  4. Next, download symbols for the Base Application using Ctrl+Shift+P and then choose Download Symbols.

  5. Customize the Base Application. In this example, we will just modify the text in the Name field on the Customer Card page to be Strong. So, in the file, we specify the following extra line of code:

    field(Name; Name)
        ApplicationArea = All;
        Importance = Promoted;
        ShowMandatory = true;
        Style = Strong;       // Show name in bold
        ToolTip = 'Specifies the customer''s name. This name will appear on all sales documents for the customer.';
        trigger OnValidate()
  6. Use the Business Central Administration Console to ensure that the settings for developing for on-premises are correctly set. On the Development tab these must be:

    • Allowed Extension Target Level is set to OnPrem.
    • Enable Developer Service Endpoint checkbox is selected.
  7. In the app.json file, in the dependencies section, make sure that version is set to the version of the System Application found in the project under .alpackages. For example:

    "dependencies": [
        "appId": "63ca2fa4-4f03-4f2b-a480-172fef340d3f",
        "publisher": "Microsoft",
        "name": "System Application",
        "version": "16.0.10037.0"
  8. Configure User Settings or Workspace Settings to include the following paths for the "al.assemblyProbingPaths" setting. For more information, see AL Language Extension Configuration.

    "al.assemblyProbingPaths": [
        "C:\\Program Files\\Microsoft Dynamics 365 Business Central\\170\\Service",
        "C:\\Program Files (x86)\\Microsoft Dynamics 365 Business Central\\170",
        "C:\\Program Files (x86)\\Reference Assemblies\\Microsoft\\Framework\\.NETFramework\\v4.8",
        "C:\\Program Files (x86)\\Reference Assemblies\\Microsoft\\WindowsPowerShell"
  9. For improved performance when working with a large project like the Base Application, see the Optimize Visual Studio Code Editing and Building Performance topic.

  10. Next, you must uninstall all extensions from the command line. If you at this point try to just publish the extension from Visual Studio Code you will get the following error:

    The request for path /BC170/dev/apps?SchemaUpdateMode=synchronize&DependencyPublishingOption=ignore failed with code 422. Reason: The extension could not be deployed because it is already deployed on another tenant.

    You get the error because the extensions are installed in the global scope. If you want to publish an extension from Visual Studio Code, within the developer scope, you will have to first uninstall and then unpublish the extensions from the command line.

    Ideally, you should uninstall the application that you want to update and all its dependencies. To uninstall the Base Application use the following cmdlet:
    Uninstall-NavApp -Name "Base Application" -ServerInstance BC170 -Force

    Use the -Force parameter to uninstall all dependencies.


    Alternatively, uninstall everything using the following cmdlet. Get-NAVAppInfo -ServerInstance BC170 | %{Uninstall-NAVApp -Name $_.Name -ServerInstance BC170 -Force}

  11. Having uninstalled, the next step is to unpublish the application and all of its dependencies. This needs to happen before we can publish it. The following command can be used if there are no dependencies to the Base Application:

    Unpublish-NavApp -Name "Base Application" -ServerInstance BC170

    But if there are dependencies on the Base Application this will give an error. To solve this, you must unpublish all the applications with dependencies on the Base Application. This is easier to do using a script that recursively removes the dependencies. Use Windows PowerShell ISE to create a new script with the following lines of code:

    function UnpublishAppAndDependencies($ServerInstance, $ApplicationName)
         Get-NAVAppInfo -ServerInstance $ServerInstance | Where-Object { 
        # If the dependencies of this extension include the application that we want to unpublish, it means we have to unpublish this application first.
        (Get-NavAppInfo -ServerInstance $ServerInstance -Name $_.Name).Dependencies | Where-Object {$_.Name -eq $ApplicationName}
     } | ForEach-Object {
        UnpublishAppAndDependencies $ServerInstance $_.Name
     Unpublish-NavApp -ServerInstance $ServerInstance -Name $ApplicationName
    function UninstallAndUnpublish($ServerInstance, $ApplicationName)
        Uninstall-NavApp -ServerInstance $ServerInstance -Name $ApplicationName -Force
        UnpublishAppAndDependencies $ServerInstance  $ApplicationName
    UninstallAndUnpublish -ServerInstance "BC170" -ApplicationName "Base Application"
  12. Save the script as unpublish.ps1.

  13. Run the script from the PowerShell commandline to handle the uninstall and unpublishing of the Base Application and its dependencies: .\unpublish.ps1


    Use "dependencyPublishingOption": "Ignore" in the launch.json file to only publish this extension. For more information, see JSON Files.

  14. Import a license with rights to publish the extension. For example:

    Import-NAVServerLicense -ServerInstance BC -LicenseFile "C:\Users\mylicense.BCLicense"
  15. Press Ctrl+F5 to publish the modified Base Application as an extension from Visual Studio Code.

The Base Application is now published with the small customization of bolding the text in the Name field on the Customer Card page.

See Also

Unpublishing and Uninstalling Extensions
Developing Extensions