The shortest period at all is two days, the gap between macOS 13.2.1 and macOS 11.7.4.

The shortest time period between any two releases in the same OS generation is six days, which is how quickly the 10.15.5 Supplemental Update 1 came out after the 10.15.5 release.

So on average, we've seen some sort of update every 44 days.

As of Febru(11.7.4's release date), it's been 8190 days since the Public Beta was released.

This version was only for the then-new PowerMac G5 and the flat panel iMac G4, and was never generally released. This figure includes the one odd macOS X release: 10.2.7.

Starting with the Public Beta and up through 11.7.4, there have been 186 macOS releases, both major and minor.

Some random notes, updated from the original post: This has happened a few times over the years. This is to keep the version numbers in the proper order, even when an older OS received an update after a major new release came out. Some entries may appear out of chronological order (i.e. Note: The Days column reflects the number of days between releases. Ⓘ Leopard - First universal binary release Ⓘ Snow Leopard - First Intel-only release Ⓘ Lion - App Store only (USB stick later) Updated SysEx manufacturer names and controller names.Ⓘ Ventura (Taxes were too high in Santa Barbara?).Shows the full name of MIDI devices and ports, better matching other apps.Fixed a bug on Macs with Apple Silicon (aka M1 or ARM) processors: when many MIDI messages were received at the same time, we would display corrupted and invalid events.It looks much nicer, and lets you copy the data as either hex bytes or text, not both mixed together. Detailed event data is now displayed using a view supplied by HexFiend, rather than plain text.

This works better with macOS’s current security systems, and makes it easier to install the app by dragging to the Applications folder. The app is now distributed as a disk image.I want to keep MIDI Monitor working for another twenty years! This will improve reliability, and will make it easier to add new features. Rewrote the app in Swift, and upgraded to newer APIs. If you're using an older version of macOS, use version 1.4.1 instead.

Photos app for mac os x 10.9.5