These Halftracks were on display at a public day in Zwölfaxing barrack. I do not know if these halftracks were Austrian Army M21.
"Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer""Austrian Armed forces", "Austrian Army", "M21 Halbkettenfahrzeug", "M21 halftrack", "Museum of Military History Vienna", "österreichisches Bundesheer"