You have already learnt about new fluorescent blue 50 rupee banknote printed in 2017 and the old banknote that was printed in 2015. Both these banknotes are legal tenders.
Today you will see three more variants of the banknote that are still legal tenders.
Obverse of ₹ 50 Banknotes Printed in 2016, 2011, and 1990s
Reverse of ₹ 50 Banknotes Printed in 2016, 2011, and 1990s