According to a press release dated 5 July 2017, Brunei and Singapore have both issued new 50-dollar polymer notes to commemorate the 50th anniversary of the Currency Interchangeability Agreement. Brunei introduced one million notes, and Singapore introduced two million notes, all at face value. Banks in both countries offered sets of notes in complimentary folders. The commemorative notes were jointly designed by Abdul Ajihis Haji Terawih, Eng Siak Loy, and Weng Ziyan. A total of 50,000 sets of Brunei and Singapore notes bearing matching serial numbers and CIA prefixes were sold for S$300 (US$220) each beginning 12 July 2017. Uncut sheets of 3, 8, and 40 notes were also packaged for sale as numismatic products.
Courtesy of KK Lim (Collectibles Arena on eBay).