Is your Mac up to date with the latest version of the Mac operating system? Is it using the version required by a product that you want to use with your Mac? Which versions are earlier (older) or later (newer, more recent)? To find out, learn which version is installed now.

  1. Because memory was a scarce resource, the authors of the Mac OS decided to take advantage of the unused byte in each address. The original Memory Manager (up until the advent of System 7) placed flags in the high 8 bits of each 32-bit pointer and handle.
  2. Two situations are considered: 8-bit-clean environments (which can be assumed), and environments that forbid use of byte values that have the high bit set.

If your macOS isn't up to date, you may be able to update to a later version.

Most likely, your input file uses a single-byte 8-bit encoding such as ISO-8859-1, frequently used to encode 'Western European' languages.

Eight Bit Byte Mac OS

Which macOS version is installed?

From the Apple menu  in the corner of your screen, choose About This Mac. You should see the macOS name, such as macOS Big Sur, followed by its version number. If you need to know the build number as well, click the version number to see it.

Which macOS version is the latest?

These are all Mac operating systems, starting with the most recent. When a major new macOS is released, it gets a new name, such as macOS Big Sur. As updates that change the macOS version number become available, this article is updated to show the latest version of that macOS.

Computer Bits And Bytes

If your Mac is using an earlier version of any Mac operating system, you should install the latest Apple software updates, which can include important security updates and updates for the apps that are installed by macOS, such as Safari, Books, Messages, Mail, Music, Calendar, and Photos.

Bits Bytes Chart

macOSLatest version
macOS Big Sur11.3
macOS Catalina
10.15.7
macOS Mojave10.14.6
macOS High Sierra10.13.6
macOS Sierra10.12.6
OS X El Capitan10.11.6
OS X Yosemite10.10.5
OS X Mavericks10.9.5
OS X Mountain Lion10.8.5
OS X Lion10.7.5
Mac OS X Snow Leopard10.6.8
Mac OS X Leopard10.5.8
Mac OS X Tiger10.4.11
Mac OS X Panther10.3.9
Mac OS X Jaguar10.2.8
Mac OS X Puma10.1.5
Mac OS X Cheetah10.0.4