Mine was due June 2024. I deferred it until this coming June 2025. I was asked if I would like a lump sum of the year's deferred money, but chose to have the increased monthly pension instead. Though living here in Thailand it will be frozen once it starts.
The person I spoke to told me that as I could buy some years, someone would be calling me to see if, and how many I would like to buy. Again, living here in Thailand with what will be a frozen pension, I am not sure if buying any extra years would be worth it.