With Mac OS X 10.4, Apple added support for Inline Attribute Data records, something that had been a part of the Mac OS X implementation of HFS Plus since at least 10.0, but always marked as "reserved for future use".
Until the release of Mac OS X Server 10.4, HFS Plus supported only the standard UNIX file system permissions; however, 10.4 introduced support for access control list–based file security, which provides a richer mechanism to define file permissions and is also designed to be fully compatible with the file permission models on other platforms such as Microsoft Windows XP and Windows Server 2003.
HFS Plus's system greatly improves space utilization on larger disks as a result.
With appropriate hardware, both encryption and decryption should be transparent.
HFS Plus volumes are divided into sectors (called logical blocks in HFS), that are usually 512 bytes in size.
At WWDC 2017, Apple announced mac OS High Sierra, in which the default file system of Mac is changed to APFS.
HFS Plus is an improved version of HFS, supporting much larger files (block addresses are 32-bit length instead of 16-bit) and using Unicode (instead of Mac OS Roman or any of several other character sets) for naming items.Formerly, HFS Plus volumes were embedded inside an HFS standard filesystem.