Technical Upgrade Steps for a NAV to Dynamics 365 Business Central

Technical Upgrade Steps: Microsoft Dynamics NAV to Microsoft Dynamics 365 Business Central

A technical upgrade focuses on moving the application and database to Business Central while keeping business logic intact. It prepares the system for functional upgrades and modern AL-based development.

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Phase 1: Running the Technical Upgrade

Step 1: Install Business Central

Begin by installing Business Central using the official setup media provided by Microsoft.
During installation, configure the required environments such as:

• Development

• Production

• Demonstration / Test

This process installs all core components, including the Business Central Server, Web Client, and Development Environment.

Once installation is complete, open the NAV/Business Central Development Environment as an Administrator to ensure you have sufficient permissions for schema and object operations.

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Step 2: Connect to the Application Database

When working with Azure SQL, connect using the following naming format:

SQLDatabaseServerName.database.windows.net

This ensures the development environment can correctly locate and authenticate against the Azure SQL application database used by Business Central.

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Step 3: Connect the Development Environment to the Server Instance

In the Database Information window:

1. Locate the Server Instance field

2. Click the drop-down arrow

3. Select Available Server Instances

4. Choose the appropriate Business Central server instance

This step links your development tools to the correct Business Central service tier.

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Step 4: Import Codeunit 1 Replacement

Business Central no longer supports direct customization of Codeunit 1.

To proceed:

• Obtain the Codeunit 1 replacement code provided by Microsoft

• Save it in a text editor

• Import it into the development environment

This replacement acts as a bridge during the upgrade and allows the system to compile successfully.

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Step 5: Compile All Objects

Next, compile all application objects:

1. Open Object Designer

2. Go to Tools → Compile

3. Select Compile All

4. Choose Synchronize schema later

This identifies inconsistencies between the application and database without making immediate schema changes.

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Step 6: Fix Compilation Errors

After converting a Dynamics NAV 2018 database to Business Central, you will likely encounter compilation errors—even in standard objects.

Common reasons include:

• Deprecated functions

• Changed system tables

• Removed C/AL constructs

Review each error carefully and fix them before proceeding. This step is critical for a stable upgrade.

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Step 7: Repair Published V2 Extensions

If V2 extensions were previously published, they must be repaired.

Use the PowerShell cmdlet:

Repair-NAVApp

For multitenant environments, remount the tenant database after completing the repair to ensure extension metadata is correctly aligned.

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Step 8: Synchronize Databases

Finally, synchronize the tenant database with the application database.
This applies schema changes and aligns metadata between the application and tenant layers.

At this point, the technical upgrade is complete.

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Phase 2: After the Technical Upgrade

While the system is now technically upgraded, several important steps remain before it is fully operational.

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Step 1: Upgrade JavaScript-Based Control Add-ins

Business Central includes newer versions of JavaScript control add-ins.

• Identify which add-ins are used

• Replace older versions

• Deploy updated add-ins to the Business Central Server

This ensures UI components work correctly in the modern client.

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Step 2: Install V2 Extensions

For single-tenant environments, install the required V2 extensions using:

Install-NAVApp

Verify that each extension installs successfully and behaves as expected.

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Step 3: Transition Custom Code

Custom logic previously placed in Codeunit 1 must now be moved into appropriate management codeunits.

This step:

• Aligns custom code with Business Central architecture

• Prepares the solution for future AL extension conversion

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Step 4: Configure Pages and Reports

After the upgrade, some pages and reports may no longer appear in search.

To fix this:

• Update object properties

• Rebuild the object search index

This restores usability in the Web Client.

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Step 5: Upload the Customer License

As the final step, upload the customer license file compatible with Business Central.

This enables:

• Full functionality

• Access to licensed objects

• Extension execution

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Summary

The technical upgrade lays the foundation for:

• Functional upgrades

• AL extension development

• Cloud or SaaS migration

Completing these steps carefully ensures a stable, supported Business Central environment ready for the next phase of modernization.

 Logical Flow (Textual Diagram – Easy to Visualise)

START
  |
  v
Install Business Central
  |
  v
Open Development Environment (Admin)
  |
  v
Connect to Application Database
(Azure SQL / On-Prem SQL)
  |
  v
Connect to Business Central Server Instance
  |
  v
Import Codeunit 1 Replacement
  |
  v
Compile All Objects
(Schema Sync Later)
  |
  v
Fix Compilation Errors
(Standard + Custom Objects)
  |
  v
Repair Published V2 Extensions
  |
  v
Synchronize Application & Tenant Databases
  |
  v
TECHNICAL UPGRADE COMPLETE
  |
  v
-----------------------------------------
POST-TECHNICAL UPGRADE
-----------------------------------------
  |
  v
Upgrade JavaScript Control Add-ins
  |
  v
Install V2 Extensions
  |
  v
Transition Custom Code
(Codeunit 1 → Management Codeunits)
  |
  v
Configure Pages & Reports
(Rebuild Search Index)
  |
  v
Upload Customer License
  |
  v
READY FOR FUNCTIONAL UPGRADE / AL EXTENSIONS
END