Yes it is mandatory. due date is 30-Jun-2021 for FY 2020-21. And there is no threshold limit for dividend payment. SFT had to be filed even if dividend is less than 10 lacs.
This will be reflected in 26AS of dividend recipient.
If company paying dividend the SFT is required to file, and the transaction code is sft 015. there is no threshold limit for filing sft, in case of dividend payment.