QuickTime 7.5.5 mac

QT 7.5 was deprecated in 2002 ... 20 years ago.

Here is the download page for QuickTime -> Apple - Support - Downloads The oldest version available there is "QuickTime Player 7 for Mac OS X v10.6.3" but the page does not specify exactly what version of QT that is, only that it requires macOS Sierra 10.12 and earlier.

Actually the oldest version is 7.6 for Tiger which of course was newer than 7.5.5.