Modding, videogames, and copyright: what is legal and what is not? (C-159/23)

Modding is a widespread practice in the gaming world that allows users to customize software and electronic devices. But to what extent is it legal to modify a video game without violating copyright law? Directive 2009/24/EC protects the source code and object code of software but not the ideas and principles of operation. It is precisely on this distinction that the Court of Justice of the European Union (C-159/23) recently ruled, establishing that modifying a game’s RAM memory does not constitute a copyright violation.

This ruling sets an important precedent: does a true “freedom of modding” exist? What are the risks and opportunities for developers and users? Let’s explore what changes for the future of video game customization.

What is modding and why is it so popular in video games?

Modding, short for “modification”, is the practice of customizing and altering software, videogames, and technological devices. Originally a form of aesthetic and hardware customization for PCs, modding has evolved into a phenomenon with significant impact on the gaming and technology industries.

In gaming, modding allows users to create new maps, change game rules, modify graphics, and even add content not originally intended by developers. This creative freedom has fostered entire communities of modders, capable of transforming a game with updates, improvements, or alternative versions. Some developers, such as Valve and Bethesda, have even integrated official tools to encourage these customizations.

Modding is also widespread in the world of electronic devices. One example is modifying the firmware of smartphones and consoles to unlock advanced features or customize the system interface. However, while open-source software generally embraces these practices, proprietary systems often impose legal restrictions and technological protections.

But to what extent is modifying software legal without violating copyright law? When does customization become an infringement? The recent ruling C-159/23 by the Court of Justice of the European Union (CJEU) has clarified these boundaries, addressing a case that sparked significant debate.

Modding and copyright: the limits imposed by EU law

Software modification is only legal within the limits established by European Union copyright law. Directive 2009/24/EC protects computer programs, but this protection applies exclusively to source code and object code.

What are they?

• Source code is the readable and modifiable form of software, written by a programmer in a programming language (such as Python or C++). It is the direct result of the developer’s creative activity.
• Object code, on the other hand, is the compiled and non-editable version of the software, the one executed by the computer.

These elements are protected by copyright because the process of writing code is a creative activity comparable to writing a literary work. However, the law does not protect the ideas, principles, or algorithms on which a program is based, as they are considered functional elements rather than creative expressions.

Article 4 of the Directive grants software owners the exclusive right to authorize or prohibit any modification of the program (see also: “The Court of Bologna on the partial plagiarism of a software – Canella Camaiora” by M. Manca).

But if a modification does not alter the source or object code, is it still a violation? For example, if a change affects the RAM memory during software execution but does not alter its structure, does it still fall under the software owner’s control?

The Court of Justice of the European Union has clarified the boundaries between lawful personalization and copyright infringement.

The CJEU ruling: case C-159/23 and its effects

The Court of Justice of the European Union (CJEU) was asked to rule on a dispute between a well-known video game publisher and a company specializing in customization software. Case C-159/23 involved a program that allowed players to temporarily modify certain game mechanics, such as gaining infinite lives, unlocking hidden features, or removing developer-imposed restrictions.

The game publisher argued that these modifications violated copyright under Directive 2009/24/EC, as they altered the gaming experience without authorization. According to this view, even though the modding software did not directly interfere with the video game’s source or object code, it still modified the game’s intended functionality, interfering with the original product.

The software company, however, defended its tool’s legitimacy, arguing that the modifications were temporary and did not permanently alter the game’s structure. The software operated on the console’s RAM, a volatile memory that records data only during gameplay, without permanently changing the original code.

The CJEU dismissed the copyright violation claims, clarifying a fundamental principle: copyright protects source code and object code, i.e., the expressive and creative components of software. However, it does not cover ideas, principles of operation, or modifications that merely influence a program’s behavior without altering its underlying structure.

Since the contested software only acted at the level of temporary memory, modifying variables that controlled game elements such as the number of lives or available options—the Court ruled that such modifications do not fall under the protection granted by Directive 2009/24/EC. In other words, modifying RAM during game execution does not equate to a copyright violation, as it does not result in a permanent reproduction or transformation of the protected program.

This ruling sets an important precedent, drawing a clear distinction between modifications that affect the creative structure of a software (protected by copyright) and interventions that act solely on temporary memory, which remain lawful.

Is there a “freedom of modding”?

The CJEU’s ruling raises a central question: do users have the right to modify the software and devices they purchase, or does copyright law impose insurmountable limits?

On one hand, software developers have a legitimate interest in protecting their creative work, preventing unauthorized manipulations that could compromise the intended user experience or enable illicit activities such as piracy. On the other hand, users and modding communities assert their right to customize software, especially when modifications do not permanently alter the code protected by copyright.

With this decision, the CJEU clarified a key point: copyright protects only the source code and object code of software i.e., the components derived from the developer’s creative work. Ideas, principles of operation, and temporary modifications to RAM are not protected, as they do not constitute a creative expression but rather a technical mechanism.

This interpretation prevents copyright from becoming a monopoly on ideas, allowing more room for innovation and technological experimentation. However, some questions remain unanswered:

• Where does customization end and infringement begin? If modding software, initially intended for temporary modifications, were later used to export data or generate alternative code, the distinction between legal and illegal use would become more complex and blurred.
• How can developers protect themselves without stifling creativity? Some companies have adopted advanced protection measures to prevent unauthorized modifications. Others, however, have seen modding as an opportunity: companies like Valve and ZeniMax Media Inc. have created official modding platforms, providing users with regulated tools to safely customize games.

So, does a true “freedom of modding” exist? The answer is far from straightforward. Modding can be a form of expression and innovation, but only if it operates within the boundaries of copyright law. The challenge for the future will be finding a balance between protecting intellectual property and allowing freedom of experimentation, ensuring that modding remains a form of creative expression rather than an abuse.