Below is a truncated version of the release notes for v2.2.0. Please be aware that there are major changes around saving to the VMU that by design will cause a build failure if you are using vmu_pkg and will break saving generally otherwise. An example of the changes needed for this, and some other more minor, API changes can be found here.

As always, in the doc folder you can find a comprehensive changelog and more verbose release notes.

What's New in Version 2.2.0

There are three major changes in v2.2.0 compared to prior releases. The first is that it didn't take 10 years! Other than that, we have a new implementation of POSIX threading and have updated the default Floating-point ABI to m4-single. A more thorough explanation of each can be found in the full release notes.

Core Functionality

• FS: . and .. handling and stat for all vfs.
• Expanded KOS_INIT_FLAG options for vfs support.
• New Priority Boosting scheme for threads.
• Fixed library loading functionality.
• Added getpeername(), settimeofday(), and expanded sysconf() support.
• Entirely new libpthreads providing enhanced support for POSIX threading.

Dreamcast Functionality

• Support for CD IRQ-based DMA, and DMA Streaming.
• Reworked APIs with strong typing for: IRQ, DMAC, bfont, Keyboard, and PVR.
• Support for SQs when using MMU.
• New Performance counter based performance monitor API.
• VMU metadata is now excluded from standard file reading and managed by API.
• Driver for the SCI interface. Accessible on DC via mod or NAOMI via CN1.

A full list of PRs included can be viewed here.