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ARTICLE · 16 MAY 2025

UK Court Rules On Reverse Engineering Of Mainframe Software

Jones Day
Jones Day
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IBM UK ("IBM") successfully enforced the terms of a mainframe license against the defendants who had created a competing software product.

United KingdomIntellectual Property
Edouard Fortunet
Edouard Fortunet
Jakob Guhn
Jakob Guhn
Rebecca Swindells
Rebecca Swindells
Sophie Burgess
Sophie Burgess
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In Short

The Situation: IBM UK ("IBM") successfully enforced the terms of a mainframe license against the defendants who had created a competing software product.

The Result: Focusing on the discussion of intellectual property rights, the court favored a strict adherence to the terms of the software license agreement when assessing use restrictions and potential breaches. Copyright exceptions conferred by Directive 2009/24/EC ("Software Directive") are limited and will be applied restrictively, ensuring that copyright owners are able to exploit their work and protect their legitimate interests.

Looking Ahead: Software licensors should ensure that their agreements are sufficiently clear to protect their intellectual property interests. Likewise, software licensees should ensure that the terms of software license agreements are adhered to, especially where the software is decompiled and shared with related entities. Such use must be in relation to the

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