In the last decades, the field of education has rapidly developed along with the development of digital technology. The recent COVID-19 pandemic has affected this development, leading to an educational revolution that involves the extensive use of online learning. This change makes it crucial to understand how teachers' digital competence has developed along with this phenomenon, as well as how teacher students are being prepared to work as future teachers. This article presents a literature review regarding how the term 'digital competence' has been understood and operationalised in the context of Norwegian teacher education in the last two decades, as well as how pre-service teachers' digital competence has been measured when researched. In the earliest findings uncovered by the review, the research is tool oriented, while a greater awareness of the professional complexity of digital competence in education emerges from 2014 to 2017. From then on, a challenge arises regarding added complexity. A somewhat complex understanding of teachers' professional digital competence (PDC) makes measuring PDC a difficult task, and it is challenging to link theoretical foundations with conducted research on the subject. This article addresses these issues and contributes to the discussion regarding the term 'professional digital competence' and how it is understood in a Norwegian educational context.