ACPI v6.1 spec has been released, apparently. I have yet to read it, so not sure what has changed yet.
The UEFI Forum has already started doing EDK-II trunk checkins for 6.1 support for UEFI.
[edk2] [patch] MdePkg: Add ACPI6.1 definition.
Add ACPI 6.1 definitions from the ACPI
Specification Revision 6.1 January, 2016.
MdePkg/Include/IndustryStandard/Acpi61.h | 2375 ++++++++++++++++++++++++++++++
1 file changed, 2375 insertions(+)
create mode 100644 MdePkg/Include/IndustryStandard/Acpi61.h
diff –git a/MdePkg/Include/IndustryStandard/Acpi61.h b/MdePkg/Include/IndustryStandard/Acpi61.h
new file mode 100644
More info:
Firmware Security 