AMSCO For AP US History

I will be taking APUSH next year. Is it really necessary to get the 2018 edition of AMSCO if I already have the 2016 edition?

Can I just use the 2016 edition to study?

There have been several updates to the test. 2016 version will be helpful - but not AS helpful as 2018

2016 version is fine. There are barely any changes year to year