At the start of the annual tax return today, things immediately went wrong. Due to an overload of DigiD, it was not possible for many people to log in. The technical problems come on top of an even bigger ICT challenge for the Tax and Customs Administration: keeping the collection of taxes going in the future.
With the tax return – a major and financially important operation – the state is estimated to collect at least 235 billion euros annually. In order to continue to do so, the outdated ICT systems must be modernized by 2026 at the latest: a race against time. We explain why this is the case using five questions and answers:
What’s the problem?
One of the major problems is that the Tax and Customs Administration used Cool:Gen software, which was developed in the 1980s, to program the computer system.
In recent years Cool:Gen has become increasingly difficult to make changes to the systems, officials say it is “a cumbersome battleship”. The Tax and Customs Administration is therefore now converting large parts of Cool:Gen to Java, another widely used programming language that is more versatile.
How is it possible that the Tax and Customs Administration uses such old software?
Cool:Gen was innovative in the 80s and 90s because it allowed you to set up systems quickly. “In those years, the Tax and Customs Administration was way ahead of its time, a real textbook example in the field of automation,” says Jurgen Vinju, professor at the Centrum Wiskunde & Informatica and TU Eindhoven.
Precisely because the software was successful for so long, the Tax and Customs Administration had few reasons to do anything about it. “You normally have to replace software after about twenty years, because it all gets older,” says Vinju. “The software seems to have become a victim of its own success in this case.”
Why is this software not easy to modernize?
Replacing an entire ICT system is quite a job, according to Vinju. “The systems have become intertwined with their environment, they grow through everything like a creeper. It takes time to understand where you can do what, without causing damage to the operational side.”
Another major problem is that there are very few tax employees who can work with Cool:Gen and carry out the modernization. Those who do are also nearing retirement. The necessary knowledge is also difficult to find outside the Tax and Customs Administration.
Another problem is that the few employees of the Tax and Customs Administration who still have knowledge of Cool:Gen have recently been assigned other rush jobs. For example, following a verdict by the Supreme Court, adjustments had to be made to the capital gains tax in box 3. As a result, the conversion of Cool:Gen was delayed by a year.
Will the Tax and Customs Administration meet the 2026 deadline?
The Ministry of Finance says it will meet that deadline, but then no unexpected things can happen. The service also asks politicians not to request any new major policy wishes until 2026. These could lead to further delays in modernization.
In a report last year, the ICT Assessment Advisory Board still expressed serious doubts as to whether the deadline could be met. Consultancy firm Capgemini also fears that the system will not be modernized in time with further delays. “A consequence of this is that the levying of income tax is jeopardized because, for example, system errors cannot be resolved (in a timely manner”), the report states.
Why isn’t the Tax and Customs Administration building a whole new system?
Due to the archive function, the systems must remain in the air. That is why everything was replaced at once, with a big bang, which officials say is too risky. They are therefore working on modernizing little by little.
Even after 2026, the Tax and Customs Administration will therefore not be rid of Cool:Gen. The software is still required to retrieve old declarations.
