What are prior user rights?

Before the filing date of a patent application, if the patented invention/utility solution has been used by a third party independently of the owner of the patented invention/utility solution . This party shall have “prior user rights”; so called the prior user. The prior user is entitled such use within the scope and volume that have already been used before the filing date of the application.

The party with prior user rights shall not be allowed to transfer such right to another person, except they transfer the whole prior user rights together with their business establishment where the prior use is undertaken.