The Logic Pro update supports 64-bit native mode, facilitates compatibility with both 32-bit and 64-bit Audio Unit plug-ins, and offers many other fixes. A long list of updates is available on .
The MainStage update also supports 64-bit mode and compatibility with both 32-bit and 64-bit Audio Unit plug-ins. Other new fixes include improved compatibility when importing layouts and patches exported from MainStage 1.x and more reliable MIDI input with grouped keyboard controls. A long list of additional improvements is listed on .
According to , the following features are not available when using Logic Pro 9.1 in 64-bit mode:
While running the updated software in 32-bit mode requires Mac OS X 10.5.7 or later, running the update in 64-bit mode requires at least version 10.6.2.