For on-premises users who are unable to get the GST rate change update you can manually create a new tax code.
Please note that if you receive the update after you have manually created the tax code, it will be over written with the system's version of the tax code.
go setup -> accounts -> tax
duplicate the 7% version
change the code
change the percentage.
you should leave the other options the same.
repeat the process for the other tax code that you will use.
you do not need to create the 8% version for all tax code.
to use the new tax code you'll need to logout and in for the system to refresh the tax code list.
the new tax code will be displayed in the tax column