The MoveS network (Free Movement and Social Security Coordination) will organise a seminar in Prague (Czech Republic) on 24 September 2018. In the first part of the seminar, current questions connected to Directive 2004/38, posting of workers and other topics will be addressed. A more general reflection on 50 years of free movement of workers and its consequences for the Czech Republic will be included. The second part of the seminar will be dedicated to a discussion on the amendment of the social security coordination Regulations. Particular aspects, which are of interest for the Czech Republic, will be discussed in more detail.