My professor told us a previous version of our textbook would be okay, but has now decided that it isn't? I currently have a class in which at the beginning of the semester, our entire class was told it would be okay to obtain a previous version of the textbook which I did because it was significantly cheaper. However, now that we are further on in the semester, the previous version is leaving out information that the new version contains. Each week, we complete a guided inquiry for this class in which we answer questions about the chapters. The guided inquiry now frequently has questions that answers cannot be found for in the previous edition. Our professor, however, only has the new edition of the text and doesn’t know which questions cannot be found in the previous edition. She decided that a good means of dealing with this would be to give us two attempts on the guided inquiry so that after we complete it the first time, we can reach out to our peers and get the information not found in the textbook.
I personally don’t think that this is fair to either the people with the new edition or the people with the old edition. The people with the old edition will have to rely on others for them to get a good grade, and the people with the new edition will have to devote time to finding the information that their peer needs and sending it to them. Because college students tend to be very busy, I don’t think that either of these is an ideal situation to be in.
However, I am not sure if this is just me being upset over the fact that I now have to spend extra time emailing someone else and waiting and hoping I get the information, or if it is a justifiable argument and I should send her an email to discuss the matter. I also don’t want to seem disrespectful, because I am sure she is just trying to do what she thinks is best as an educator so that we have all the information we need to become successful teachers. I am just not sure how an email from me would be received.
Edit to add: This is an online class so in order to get the pages from someone else, I would have to email and ask them to send me either pictures of their text or pictures of their answer. We only have three chapters left, so I was going to ask if maybe she could just scan those chapters for those of us with the old edition and post them on our class site with the other information because she did this for us at the beginning of the school year when everyone was still waiting to receive their textbook. Also, our university library is closed due to COVID and only providing online resources right now. Another reason that I didn't mention prior to this is that the class had issues finding the current edition of the text, and that was the reason a lot of people got the older version. The newer version at the time wasn't available through Amazon or Chegg and our school bookstore sold out pretty quickly. Also, yes this is an educator preparation class.
I've been both in situations where I told my students &quot;I've looked at the 1st edition of the text and it's OK to use it&quot; and &quot;I've looked at the 1st edition of the text and it's not OK to use it&quot;. It sounds (unless I misunderstand your story) that your professor never looked at the prior edition and just assumed that it would be OK. I hope that &quot;never assume&quot; will be one of the lessons learned in this class by everyone, including your professor.
The professor tried to mitigate their mistake. (Other possible solutions might be to limit the topics of the guided inquiry to the material in the old edition, but that would not be fair to the students who do have the new edition.) Clearly, this creates a huge inconvenience for you (and the other people with the old edition), but also, more importantly, you're missing out on the material that's in the latest edition and is missing in the one you have.
My advice to you is twofold:

You're missing out on gaining the knowledge which is the goal of your being in this class and in school. You're not learning as much as the other students who have access to the current edition. Get hold of the current edition of the text book (buy it new, buy it used, rent it, download it for free from pirate sites, borrow from somebody). It may cost you, but the alternative is that you won't learn in this class whatever you've set out to learn.

Do not say anything to the professor. Nothing good is likely come out of it. The professor already knows that students who have the old text are inconvenienced. You have nothing new to say. The professor sounds very unlikely to change anything again, but also sounds like the type who might retaliate and dng your grade for complaining. If your school conducts course evaluations at the end of the semester, explain there clearly what went wrong.