The Court of Justice of the European Union, in a judgment important not only for IT environments, decided that if a computer program does not work, in certain cases it can be decompiled

The buyer of a computer program has the right to decompile it in order to remove errors and thus does not infringe the copyright, the Court of Justice of the European Union found in a judgment important not only for IT communities, on 6 October 2021.

Computer programs are considered works and therefore are subject to copyright in Poland. However, these are specific works, therefore, at the EU level, a separate directive on the legal protection of computer programs (91/250/EEC) has been dedicated to them. It regulates a number of technological aspects related to the use of software, including its possible decompilation. The buyer of the program usually does not have access to its source code. He gets it in the form of machine code. In order to change something in it, it is necessary to decompile it. The question, however, is when is it legally permissible.

Decompilation therefore constitutes an alteration of the program’s code, which involves a reproduction – at least a partial and temporary one – of that code, and a translation of the form of that code.

Decompilation of a computer program involves the performance of acts, namely the reproduction of the program code and the translation of the form of that code, which in fact come within the exclusive rights of the author, as defined in Article 4(a) and (b) of Directive 91/250.

EU legislature thus intended to limit the scope of the exception for interoperability, as laid down in that provision, to circumstances in which the interoperability of an independently created program with other programs cannot be carried out by any other means, but only by means of decompilation of the program concerned.

Such an interpretation is supported by Article 6(2) and (3) of Directive 91/250 which prohibits, inter alia, the use of information obtained by means of such decompilation for goals other than achieving such interoperability or developing similar programs, and which further excludes, in general terms, any use of such decompilation that would unreasonably prejudice the rightholder’s legitimate interests or conflicts with a normal exploitation of the computer program concerned.

Such a problem arose before a Belgian court. One of the central offices there purchased a license for specialized software. The problem was that it contained errors that blocked the functioning of some elements of the system. Therefore, the office decompiled the software and corrected its code. The system provider considered this to be an unlawful interference with his exclusive rights and brought a claim for damages. The court of second instance referred two questions for a preliminary ruling to the CJEU.

The indicated directive in Art. 6 mentions the possibility of decompiling the program without the consent of its authors, but only when it is necessary to achieve interoperability with other software and after meeting additional conditions. In the case pending before the Belgian courts, the issue was not that of interoperability but an error. The buyer first corresponded with the authors of the program, asking them to remove it. When there was no reaction, the buyer recompiled the program, and then turned off one of the software functions that was causing it to malfunction.

This involves the issue of Art. 4 letters a and b of the quoted Directive, listing proprietary activities that normally cannot be performed without the consent of the software developers, unless necessary to correct the error. Among them, there is duplicating the program code or its translation. However, these provisions do not mention in any way decompilation, which is determined separately by art. 6 of the Directive.

Despite this, the CJEU found that decompiling to correct a bug is permissible without the consent of the authorized software developers. It is inextricably linked with the duplication and translation of its code. And these activities, in accordance with Art. 5 of the Directive are legally permissible as long as their implementation is necessary for the use of the program.

This interpretation is confirmed by the wording of Art. 6 sec. 1 of the Directive, which – although it refers to decompilation in accordance with its title – clearly refers to the duplication of the code and the translation of its forms within the meaning of Art. 4 lit. a) and b) of the Directive. It follows that the concept of decompilation within the meaning of that Directive does indeed fall within the exclusive rights of the author of a computer program laid down in the latter provision, ‘the Court explained in its judgment.

The company that created the software argued that Art. 6 introduces the only exception for decompilation, and is limited only to what is necessary to achieve interoperability. The CJEU did not agree with this argumentation. In its opinion, a combined reading of the provisions, including the recitals of the Directive, does not provide grounds for such an interpretation. The legislator wanted to separate the interoperability issue in a separate provision from limiting the possibility of decompilation. Without it, the power to rectify errors expressly granted in another provision would often remain illusory.

The main conclusions of the Court are as follows:

1. Article 5(1) of Council Directive 91/250/EEC of 14 May 1991 on the legal protection of computer programs must be interpreted as meaning that the lawful purchaser of a computer program is entitled to decompile all or part of that 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.

2. Article 5(1) of Directive 91/250 must be interpreted as meaning that the lawful purchaser of a computer program who wishes to decompile that program in order to correct errors affecting the operation thereof is not required to satisfy the requirements laid down in Article 6 of that directive. However, that purchaser is entitled to carry out such a decompilation 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 in that program.

See Judgment of the Court of Justice of the European Union of October 6, 2021 in case C-13/20