If I do a certification course in IT, will I need to retake all English language tests like IELTS in Germany?

It depends on the requirements of the specific IT certification course provider in Germany.

If your current IELTS score is still valid (typically within the last two years) and meets the course's minimum requirement, you may not need to retake the test. However, some providers may require a recent English proficiency test regardless of previous scores.

Check the language requirements for your chosen course. If your score has expired or doesn't meet their criteria, you will need to retake the test.