Hi @Juliette Lahey,
Thank you so much for reaching out!
When completing a Pre-K or Pre-K–3rd recertification, observers can use either the first or second edition of the CLASS® manual, and upon completion can use either version for observations.
You will get the chance to upgrade to CLASS 2nd edition through the Transition Support Course. If you are only certified in Pre-K, the recertification is for both Pre-K and K-3, so we would highly recommend the transition course prior to recertification.
Here is the link to the store page where you can select which option you'd prefer. Also, the "test only" version only has your typical online recertification, but in this case will be for 2nd edition, whereas the recertification bundle also includes a physical copy of the CLASS 2nd Edition manual.
I really hope this helps, you can find more information on 2nd edition for observers here!
Best,
Allison