The 10,000 dollar note remains legal tender in Singapore but is being withdrawn from circulation together with the 1,000 note:

"Note: MAS has stopped issuing the following notes as a pre-emptive measure to reduce the potential money laundering and terrorism financing risks associated with large denomination notes:

The $1,000 notes with effect from 1 January 2021. The $10,000 notes with effect from 1 October 2014. Existing $10,000 and $1,000 notes in circulation remain legal tender in Singapore and can continue to be used as a means of payment for goods and services."

https://www.mas.gov.sg/currency/circulation-currency/circula....