The old 2000 and 5000 HUF banknotes issued before 2016 were withdrawn on 31 July 2017. Only the new, upgraded banknotes can be used for cash purchases from 1 August 2017.
It is important to note that the old 2000 and 5000 forint HUF will not lose their value. After the withdrawal date, credit institutions and the post office will exchange the old banknotes for legal tender for three years, and the MNB will exchange them for legal tender of the same denomination free of charge for twenty years, i.e. until 31 July 2037.
More information: https://www.mnb.hu/en/banknotes-and-coins