QuickTime 7 is still quite popular but that will change soon, because the application is only available in 32-bit and Apple has made it clear that a 64-bit version is not offered, as Jason Snell reports.
The tool becomes still available for download and that has good reasons: The successor QuickTime X lacks some editing functions. In addition, the new version is not extendable by codecs and so can not convert certain video formats. There is also another problem. Third-party software uses QuickTime 7 and takes advantage of the features of the application without users noticing. They will, however, if they diligently update macOS and the successor of macOS High Sierra does not support 32-bit apps anymore. Then the applications should not work properly anymore.
Starting with macOS High Sierra 10.13.4, users starting a 32-bit app are generally warned about the end of this era. Apple does not want to support 32-bit apps after macOS High Sierra. As of June 2018, 64-bit support is mandatory, Apple said.