When is the right time to upgrade from NAV to Business Central? And which version is the best option?

In order to make the right choice, it is important to know the features of NAV and Business Central versions and, in particular, the programming languages they use.

The programming language used to develop and customize NAV is C/AL, while the new one is called just AL. Both AL and the new software architecture are designed for cloud and to support a smooth and frequent version upgrade.

The replacement of C/AL with AL happened gradually, and for a period of time, Business Central version supported both languages, as explained in the table below.

Version AL C/AL
Business Central 15 e successive Yes
Business Central 14 Yes Yes
NAV 2018 Yes Yes
NAV 2017 Yes
NAV 2016 and previous Yes

Another important change made by Microsoft, while introducing Business Central, is the duration of the support for old versions. Up to Business Central version 14 the support was extended for 48 months after the end of the release (i.e. from the issue of the following version), for Business Central version 15 and all of the following the duration of support is reduced to 12 months.

Basically, from version 15 a regular and frequent upgrade is needed not to lose software support. This is obvious for SaaS applications but applies for on premises installations too. Customers with on premises installation used to have a larger time window to manage upgrade, but this will be no longer true.

Based on what is written above, it came out that Business Central v14 is a “special” version for some reasons:

  • It belongs to the new generation (Business Central) and uses AL language
  • It is the last version supporting C/AL too
  • It benefits of a longer lasting support compared to the following releases

For customers now running NAV with C/AL customizations, an upgrade path to AL needs to be planned: AL is the language for current and future release, while SaaS cloud architecture is (and will be) the base platform for Business Central, the one which Microsoft focuses on for developments and new features.

It is also clear that moving customizations from C/AL to AL is quite a big job both for time and money, on the other hand an upgrade within the C/AL language is a lighter job.


An interesting option is to make a two-step upgrade: the first step from NAV to Business Central version 14, still using C/AL language, the second step moving to AL language in a following release.

Since version 14 has 48 months support, there is more time to manage the second step, which is the most challenging.

To use this opportunity the first step is to be done quickly, because version 14 is available only until the end of September 2020.

AL BC Business Central C/AL Nav Upgrade