Update 19.04.2021: No other countries have issued additional entry notifications. Please note that in addition to the entry notifications, many countries also require the submission of a negative PCR test. The requirements differ greatly. Therefore, it is advisable to inform yourself before departure about any test obligation that may be necessary.
Business trips are associated with special difficulties in times of COVID-19. This does not only apply to the practical problems of implementation, for example due to restricted travel options or special regulations for entry and quarantine. One special regulation that many countries have adapted is an entry declaration prior to travel.