HomeInsightsCourt of Justice of European Union holds that a lawful acquirer of a computer program can correct errors that affect its functions through decompilation if it is necessary for use in accordance with its intended purpose

The Belgian Court of Appeal referred two questions to the CJEU, essentially asking whether decompilation is permitted under Article 5(1) of the Software Directive (91/250/EEC) for the purpose of correcting errors affecting a program’s function, including where the correction consists in disabling a function that is affecting the proper operation of the program, or whether decompilation is only permitted in the situations set out in Article 6 (which specifically allows decompilation in certain circumstances only). If decompilation for error correction is permitted under Article 5(1), the Belgian Court of Appeal has also asked whether the conditions set out in Article 6 must be satisfied.

Article 5(1) provides: “In the absence of specific contractual provisions, the acts referred to in Article 4(a) and (b) shall not require authorisation by the rightholder where they are necessary for the use of the computer program by the lawful acquirer in accordance with its intended purpose, including for error correction”.

Under Article 6, under the heading “Decompilation”, the authorisation of the copyright holder is also not required where the reproduction of the code or the translation of the form of that code, within the meaning of Articles 4(a) and (b), is indispensable to obtain the information necessary to achieve the interoperability of an independently created computer program with other programs, provided that certain conditions are met.

Articles 4(a) and (b) set out a non-exhaustive list of the copyright holder’s exclusive rights, which are stated to be subject to Articles 5 and 6, including the exclusive right to make or authorise the translation, adaptation, arrangement and any other alteration of a computer program and the reproduction of the results thereof. There is no mention of decompilation as such.

The question was, the CJEU said, whether decompilation came within the scope of Articles 4(a) and (b) despite there being no mention of it.

The CJEU noted that a computer program is initially written in the form of a “source code” in a comprehensible programming language before being transcribed into a functional form that the computer can understand, i.e. into the form of an “object code”, by means of a specific program called the “compiler”. The process of transforming the source code into the object code is called “compilation”. Both the source code and the object code, as two forms of expression of the program, are protected by copyright under Article 1(2) of the Directive.

“Decompilation” is a reverse of the compilation process, i.e. the reconstruction of the source code from its object code, carried out by the means of a decompiler. As the Advocate General noted, decompilation produces a version of the program called “quasi-source-code”, which is then compiled into object code allowing the program to function. Decompilation therefore constitutes an alteration of the program’s code, which involves a partial or temporary reproduction of that code, and a translation of the form of that code. Therefore, the CJEU said, decompilation involves reproduction and translation, both of which are within the exclusive rights of the author defined in Articles 4(a) and (b).

However, Article 5(1) allows the lawful purchaser of a computer program to perform all the acts listed in Articles 4(a) and (b), including reproduction and translation, without prior authorisation from the copyright holder, provided that it is necessary for the use of the program, including for the correction of errors affecting its functioning.

The CJEU dismissed Top System’s argument that Article 6 meant that the only permitted decompilation is that undertaken for interoperability purposes. In the CJEU’s view, the EU legislature intended Article 6(1)(b) to limit the scope of the interoperability exception to circumstances in which the interoperability of an independent program with other programs could not be carried out by any means other than decompilation.

Further, the CJEU said, Article 5(1) has a different purpose to that of Article 6. Article 6 was intended to govern the question of the interoperability of independent programs with other programs, without prejudice to the provisions in Article 5(1) enabling the lawful purchaser of a program to use that program normally. To find otherwise, the CJEU said, would undermine the effectiveness of the intention to allow lawful purchasers of a program to correct errors, thereby preventing the use of the program in accordance with its intended purpose.

Therefore, the CJEU held that Article 5(1) 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 of disabling a function that is affecting the proper operation of the program.

As for whether such lawful purchaser must satisfy the requirements set out in Article 6, the CJEU said that given that Articles 5 and 6 have different purposes, the requirements of Article 6 are not applicable to the exception set out in Article 5(1).

However, decompilation under Article 5(1) is subject to certain requirements:

  1. it must be necessary for the use of the program by the lawful purchaser in accordance with its intended purpose, which includes the correction of an error, i.e. a defect that affects the program, causing it to malfunction;
  2. it must be necessary for the lawful purchaser to use the program in accordance with its intended purpose, which in most cases involves modification of the program code and the implementation of that correction, which requires access to the source code, or at the very least, the quasi-source code; it is not “necessary” where the source code is lawfully or contractually accessible to the purchaser;
  3. it is subject to “specific contractual provisions”, which cannot include a ban on the correction of errors, but can include provisions on the manner in which decompilation can be carried out, meaning that the lawful purchaser of a program is, in the absence of specific contractual provisions, entitled to perform, without authorisation from the copyright holder, the actions set out in Articles 4(a) and (b), including decompilation, insofar as is necessary to correct errors affecting the operation of the program; and
  4. the lawful purchaser of a program who has decompiled the program to correct errors cannot use the result of the decompilation for purposes other than the correction of those errors and it cannot reproduce the result.

(Case C-13/20 Top System SA v Belgian State EU:C:2021:811 (6 October 2021) — to read the judgment in full, click here).

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