Well, SQ was kind enough to send me this email today:
I believe my miles were already extended once automatically so will they be extended again?
I received this email yesterday
In view of the Covid-19 outbreak, we will be extending the validity period of your KrisFlyer miles by six months, and they will now expire between March 2021 and June 2021 respectively. For example, KrisFlyer miles expiring on 30 September 2020 will now be valid until 31 March 2021 after the extension.