READ CAREFULLY: After reading many comments about this it seems to work for some people but not others. Either people are doing it wrong or it just doesn't work for everyone.
I personally haven't updated my snapchat yet so I have not tried this technique out. I hope it works for you, if it doesn't, just know I am the messenger. Good luck Snapchatters!
1. Delete the app
While it will say that all your data will be deleted, don't freak. All your previous snaps and contacts will still be there.
2. Open your phone settings and go to iTunes and App Stores, turn off "automatic downloads" for Apps and Updates.
You may not need to turn off both, but per directions it states to switch off both... and why change it if it works? (You hear me Snapchat?!)
3. Re-download Snapchat
"Hello darkness, my old friend...."
4. Type your username in the log in screen BUT DON'T LOG IN! Instead, click on "Forgot your password?"
It's going to get a little complicated, but just stay with us. We got you.
5. Snapchat will ask you how you want to reset your password. Choose to reset your password via PHONE.
Everyone says this part is super important, so do it OK?
6. Now you get to prove you're not a robot by clicking pictures of ghosts.
Why is the logo a ghost anyway...
7. Snapchat is going to be sly and ask for your digits. Type in your cell number and hit "Continue"
We're almost there!
8. You'll receive a text from Snapchat with a confirmation code. Put that code in the app.
This will all be worth it. We promise.
9. Choose your new password.
And don't forget it like me...
10. Now re-open your app and BAM! Old Snapchat is back!