...following as we are also on 23.1 (in USA, NJ/PA taxes).  I actually canceled my annual update with our partner because a year-end update wasn't required and the payroll tax update is usually pretty simple and doesn't require individual machine updates.

HI there! 

It depends on where you are. Here is a blog that discusses the supported versions.

Canada - The supported version for Canada is 23.2. So if you are in Canada, you'll want to upgrade to version 23.2 and then apply the latest year-end payroll tax update. 

United States - If you are in the US, the supported version is 23.1. I would recommend updating to the latest update so that you have everything included with 23.1. You will also want to download and update the latest year-end payroll tax update. 

Hope this helps to clear up the confusion.