The first versions of Microsoft Dynamics NAV were released in the late 1980s as Navision running on MS-DOS and AS-400. Many of the fundamental architectural concepts were introduced in this version, and many of the objects go as far back as these days.

The language has always been updated and modernized, but Navision and Microsoft always ensured that existing code could be brought forward.

During its life cycle, Dynamics NAV had two moments when the software has had major platform changes. The first change was moving from the DOS platform to Windows in 1995, and the second and last change was the introduction of the three tier stack in 2009.

Both the platform changes allowed developers to bring forward existing applications, ensuring the investment that was made in the intellectual property.

This results in an ecosystem with a large amount of legacy code. Some of the existing Dynamics NAV objects go as far back as 30 years, including the partners and customers' code.

When Navision was originally written by the owners of the company, Design Patterns had a strong presence in the application, but the software has grown organically and has been touched by many other developers since then.

This leads to a potential challenge of having to redesign the legacy code from time to time. Since C/AL is an open code, and others can customize our code, we have to be careful in rewriting it since we might break a change that is being made outside the scope of our project.

We will discuss a few options that will allow us to refactor our application, while maintaining the upgradability for our application.