The aim of the study was to investigate catalogers’ practice, knowledge and learning, and if and how previous experience makes a difference and also investigate the need for knowledge in underlying conceptual models. The National Library of Sweden (KB) has developed the new system Libris XL which is based on a new user interface, new conceptual models and the use of linked data. I have performed observations and interviews with six catalogers working in public libraries and university libraries. Qualitative content analysis has been conducted. The concepts of catalogers’ repertoire and community learning constitutes the theoretical framework of this study. The need for knowledge in FRBR is not seen as absolutely necessary but catalogers see the conceptual model as interesting and helpful but also confusing since FRBR´s four levels are not used in the interface. Experience from previous cataloging system was not considered as an advantage in the early transition from Voyager to Libris XL but when they have learned the interface, the overall knowledge in cataloging can be useful in making resource description richer. Colleagues both at own and others’ workplace, seem to play an important role in learning and working in Libris XL and discussions are held in daily conversations and planned meetings. MARC21 is still useful to know. Tools for discussion online such as Microsoft Teams and Libris Supportforum was also important particularly in the early stages of transition. KB´s own resources such as instruction videos, texts about RDA and help texts, as well as university library manuals are used. Seeking answers in existing RDA-posts is also a strategy. RDA Toolkit is seldom used.