Mac OS 7.5.1, otherwise known as System 7.5.1 or System 7.5 Update 1.0, was released shortly after the release of System 7.5. Released in March 1995, the update, encompassing four floppy disks, not only was a bug-fix, but also added some enhancements to the Mac OS. Other noticeable changes: More Macs could now be turned off by using the Power key. With Mac OS 7.5.1's release, QuickDraw, too, was made "native", code-wise. The "secret about box" of System 7.5 was broken; however, through very tricky means, it was still restorable, and with Mac OS 7.5.2, a new one came through very soon.