I just read the following in The Local:
Austria’s Health Minister announced changes to the validity of the
Green Pass. The country will follow European Union’s directives, and
the booster shot should be valid for 12 months, he said.
The Pass will be valid for six months for double vaccinated or
This is a change from the previous 270 days validity for the booster. I do not see this change reflected yet on the official gov. site.