Originally Posted by ohmark

Says here it will re-open after renovation in March, 2024 as an Autograph Collection (Marriott) property. "**Currently the hotel is closed as an extensive renovation is taking place as well as a re-branding of the property. The re-opening of the hotel is planned for March 2024. When the hotel re-opens it will open as an Imperial Riding School, Autograph Collection.** More information on this brand-new hotel will be coming up soon." Imperial Riding School Renaissance Vienna Hotel (closed for renovation until March 2024) - Vienna, AT Meetings and Events | Cvent
Also, while the website does not show current availability of rooms, it still appears on the Bonvoy website. Hotel in Vienna, Austria City Center | Imperial Riding School Renaissance (marriott.com)