This is a retroactive change?

Does that mean a new release is needed, or do people down there not use the tzdb info? Or does conclusion mean no one is there anymore?

On March 14, 2018 10:23:13 PM UTC, Steffen Thorsen <thorsen@timeanddate.com> wrote:
Australian Antarctic Division informed us:

With the conclusion of the Australian Antarctica Division’s aviation 
program for the 2017/18 season, please change your time for Casey 
station to *UTC +8*  on Sunday 11th March (this change will take place 
on 11th March at 4am (UTC +11)).

Best regards,
Steffen Thorsen - timeanddate.com