VB Migration Partner

Fast conversion of the Danske Bank Group Teller System’s 350,000 lines of code
from the VB6 to .NET

Client Challenge

Danske Bank is the largest financial enterprise in Denmark and one of the largest in the Nordic region. The Group Teller System was implemented in the Bank’s branches in 2001, and since then various new functionality has been developed for the system. Microsoft no longer supports the VB6 IDE, so the bank decided to convert it to the .NET platform.

Branch Systems in Retail Solutions were given the assignment to convert the Group Teller System from the VB6 platform to the .NET platform. The application consists of 350,000 lines of code, a fact that ruled out the option of manual conversion. The company therefore chose VB Migration Partner to support the conversion, since this tool is developed particularly to support conversions from VB6 to .NET. This decision has meant a fast conversion and also brought to a noticeably improved conversion quality.


”VB Migration Partner allows us to automate large parts of the conversion work, and, since the conversion is 1:1, the tool further offers the advantage of bringing all functionality to the new platform,” says Michael Munk Lerskov, Project Manager. ”In terms of effort, using VB Migration Partner is significantly more efficient than manual conversion or rewriting from scratch, especially considering that banking applications require very rigorous testing plans. As a matter of fact, much of the effort was spent on quality assurance, as the project has been focused on securing a high quality of the finished product”.

”If we had to carry out the conversion manually, we could easily overlook some functionality, since not everything is fully documented.”

The project has been much dedicated to ensuring that users will notice no difference when the conversion is finished. A lot of tests have therefore been run before final conversion of the system. In addition, super users from all brands using the Group Teller System have spent six weeks testing the system in every way possible.

”We have spent a lot of time testing the system. When in doubt about whether the new solution fully matched the solution on the old platform, we checked the specific solution on the old platform. The old system has thus been normative in developing the new solution.” says Michael Munk Lerskov.

An advantage of converting to the new development platform is far better and up-to-date development tools. For example, it now takes 15 minutes to ”build” a new version of the system in the development environment as opposed to previously 3 hours.
The platform also provides a more effective development basis, as developers have a lot of functionality “handed to them on a plate”. This will be useful in the future development of the Group Teller System.

Further, the functionality allows automatic tests, which will enable us to improve quality and make future new versions of the system in less time.
After the conversion the Group Teller System was successfully deployed on more than 2.000 clients in 7 different countries and in 5 different languages. Training of the users was not needed because the user interface was similar to the interface of the VB6 version. This is an additional advantages of using VB Migration Partner, that the converted GUI is almost identical to the original one.