According to an article in The Business Standard, Bangladesh Bank planned to introduce a new 50-taka note on 15 December 2019. The existing 50- and 10-taka notes (B351 and B349, shown below) are similar in color, leading to confusion in public transactions. The new 50-taka note (B351.5a) is reddish orange to help distinguish between the denominations. The new notes will circulate in parallel with the existing notes.
Courtesy of Mohammad Raihan.
Like B351.5a, but new date (2021).
Courtesy of Ikbal Shahazad.