::
The material doesn’t change much from year to year, so you’re safe there for the most part.
You can find the summary of changes here: https://irfanullah.co/wp-content/uploads/2015/07/Level-I-2015-2016-Program-Changes.pdf
It’s a value question – if you can easily afford the material, then I’d say get the newest stuff (as you say you’ll get better access to materials, and won’t have to wonder about the accuracy of the material all the time).