Maya 2022 provides MtoA 4.2.1 which includes new features, performance improvements, and bug fixes.
Maya 2022 includes MtoA 4.2.1 which introduces Arnold 6.2.0.1, and is a feature release that brings light mixing, bloom and interactive denoising through imagers, better USD support to improve your experience working with USD in Maya, an improved layout to the Arnold Render View, and OSL syntax highlighting to the OSL shader.
For a complete list of features, see the Arnold for Maya release notes.