A Very Old Textbook

So just how old are some of the textbooks that are still being used in the Post Falls School District? I’ll let Facebook Friend Scott Peterson spell it out: ” So my niece Zoe, a freshman at Post Falls High, texts me a picture after receiving her English Grammar and Composition book today. I guess if Post Falls School District ever needed to pass a levy it would be now. Sad part is my name is not the oldest of the bunch.”

Question: Can you get away with old textbooks for a subject that changes so little, like English grammar, right?