Top System v. Belgian State (Case C-13/20) is a preliminary ruling of the Court of Justice of the European Union (CJEU) of 6 October 2021. The software developer Top System SA sued the Belgian State after SELOR, the Belgian federal government’s recruitment selection office and Top System’s licensee, decompiled part of Top System’s framework software to disable a function that was causing problems. The CJEU held that a lawful acquirer of a computer program may decompile it, in whole or in part, to correct errors affecting its operation, without satisfying the conditions of the separate decompilation-for-interoperability exception, but only to the extent necessary for the correction and in compliance with any conditions in the contract with the rightholder.[1]
Background
Top System is a Belgian company that develops computer programs and provides IT services. Since 1990 it had worked with SELOR, providing IT development and maintenance services. At SELOR’s request it developed several applications for submitting and processing applications online, which combined functions from its own framework software, the “Top System Framework” (TSF), with functions built for SELOR’s needs. SELOR held a user licence for those applications.[1]
On 6 February 2008 SELOR and Top System agreed the installation and configuration of a new development environment and the migration of SELOR’s application sources into it. Between June and October 2008 the parties exchanged e-mails about operating problems affecting applications that used the TSF, without agreeing how to solve them.[1]
The dispute
On 6 July 2009 Top System sued SELOR and the Belgian State in the Brussels Commercial Court, seeking a declaration that SELOR had decompiled the TSF in breach of Top System’s exclusive rights, and damages for the decompilation and copying of source code from around 18 December 2008. The case was transferred to the Brussels Court of First Instance, which in essence dismissed the claim on 19 March 2013. After SELOR was integrated into a federal public service, the Belgian State replaced it as defendant.[1]
On appeal Top System argued that Belgian law allowed decompilation only with the author’s authorisation or for interoperability, and not to correct errors. SELOR acknowledged that it had decompiled part of the TSF to disable a defective function. It argued that it was entitled to do so to correct design errors that made the software impossible to use for its intended purpose, and relied also on its right to observe, study and test the program to understand the ideas and principles behind the problem functions.[1]
The Brussels Court of Appeal asked the CJEU whether Article 5(1) of Directive 91/250/EEC, which applied at the time and was later codified as Directive 2009/24/EC, allows a lawful acquirer to decompile a program to correct errors, including by disabling a function, and if so whether the conditions in Article 6 of the directive, the decompilation exception, or any other conditions must also be met.[1]
Decision or outcome
Decompilation to correct errors is allowed
The CJEU held that decompilation, which reconstructs a “quasi-source code” from the object code, involves reproduction and translation of the code and so falls within the rightholder’s exclusive rights under Article 4(a) and (b). Article 5(1) allows a lawful acquirer to perform those acts without authorisation where they are necessary for using the program for its intended purpose, “including for error correction”. It followed that a lawful acquirer may decompile a program to correct errors affecting its operation.[1]
The court rejected Top System’s argument that Article 6 makes interoperability the only permitted ground for decompilation. Articles 5(1) and 6 have different purposes: Article 6 concerns the interoperability of independently created programs, while Article 5(1) lets a lawful acquirer use the program as intended. Reading Article 6 as exclusive would undermine the right to correct errors, which in most cases, especially when disabling a function, requires access to the source code or at least the quasi-source code.[1]
The conditions that apply
The Article 6 conditions do not apply as such, but the court set out conditions drawn from Article 5(1) itself:[1]
| Condition | What the court said |
|---|---|
| An “error” | In its usual meaning in computing, a defect that causes the program to malfunction, and that affects its use for its intended purpose |
| Necessity | Decompilation cannot be regarded as necessary “where the source code is lawfully or contractually accessible to the purchaser” |
| Contract | The parties cannot contractually prohibit every possibility of correcting errors, but may organise how it is done, for example by agreeing that the rightholder will provide corrective maintenance; absent specific provisions the acquirer may decompile without consent as far as necessary |
| Limited use | The result may be used only to correct the errors; any reproduction or distribution of the resulting code for other purposes still requires the rightholder’s authorisation |
The operative ruling was that the lawful purchaser is entitled to decompile all or part of a program “in order to correct errors affecting its operation, including where the correction consists in disabling a function that is affecting the proper operation of the application of which that program forms a part”, without meeting the Article 6 requirements, but “only to the extent necessary to effect that correction and in compliance, where appropriate, with the conditions laid down in the contract with the holder of the copyright”.[1]
The case then returned to the Brussels Court of Appeal to apply the ruling to the facts; no published decision of that court was reviewed for this article.[1]
Significance for software licensing and SAM practice
The dispute arose from a long-running development and maintenance relationship in which vendor and customer disagreed about how to fix operating problems. The ruling defines how far an EU licensee can go in fixing licensed software itself when the vendor does not.[1]
- Maintenance terms matter. Because contracts may organise error correction, a clause reserving corrective maintenance to the vendor can shape what the licensee may do. A licence cannot, however, exclude every possibility of correction.[1]
- Source code access. If the licensee lawfully has the source code, for example under the contract, decompilation is not necessary and the exception does not apply.[1]
- Narrow scope. The exception covers correcting errors that affect intended use, not adding features or reusing the code. Using decompiled code beyond that purpose is outside the exception.[1]
The ruling sits alongside IT Development v. Free Mobile, in which the CJEU held that a licensee’s unauthorised modification of a program in breach of the licence is an infringement of intellectual property rights. Together they mark the line between modifications a licensee may make without consent and those that infringe.
Lessons learned
- A licence cannot remove every possibility of correcting errors, but it can organise how errors are corrected. The court gave as an example an agreement that the rightholder will ensure corrective maintenance.[1]
- Decompilation for error correction is not “necessary” where the source code is lawfully or contractually available. The exception depends on necessity.[1]
- Code obtained by decompiling may be used only to correct the errors. Reproducing or distributing it for other purposes still requires authorisation.[1]
- Where support disputes leave a licensee unable to use software, the error-correction exception may be relevant, within strict limits. SELOR relied on it after failing to agree a solution with its developer, and the court confirmed that disabling a malfunctioning function can be a correction.[1]