What exactly am I supposed to do for OAuth 2.0 and https update?

I am a php developer. I created an application using fbml(non iframe) and didn't check roadmap regularly. Today I received an email saying update to OAuth 2.0 and HTTPS by October 1st or the apps may be disa开发者_Go百科bled. I went through the documentation but could not get what exactly I am supposed to do.

From what I understood. for https we need to enable or buy ssl for our site and make https://example.com/facebookapps_folder/ accessible and fill the new url in Secure Canvas URL Is that right?

I am confused about OAuth 2.0.For this do we need to change the whole code and libraries we are referring to. Where can I get how do I change it. I see some php examples but could not find clue what needs to be changed? I think it is way authentication is being done, but I do I do that.

If I fail to do it immediately(as only 3 days left) is that any way I can save my application being disabled?

Make sure you have implemented Oauth2.0 for authentication .. Also you will need an SSL certificate for your app to support https:// protocol