This article explores the use of the Teacher21 Model for the diagnosis and development of teachers' digital competencies. The Teacher21 Model is based on the European Framework of Reference for Teachers' Digital Competencies and divides them into six domains: professional engagement, digital resources, teaching, digital assessment, student support, and supporting students' digital competencies. The paper presents the results of the analysis of data obtained from a survey that included three groups of respondents: future (prospective) teachers, future (prospective) ICT methodologists and current teachers. The aim of the research is to find out how these groups perceive their digital competencies in relation to the Teacher21 Model and to identify differences between them. The results showed that all three groups have an average level of digital competencies, with the highest level in the area of professional engagement and the lowest in the area of digital assessment. The paper goes on to offer recommendations for developing teachers' digital competencies in line with trends in education and highlights the importance of the quality of education in the digital age.