Regarding Oauth 2.0 & https from October 1st

I want to know several things ab开发者_开发问答out new changes that will be applicable from October 1st that are Oauth 2.0 & https.

Will it be compulsory to provide https link when creating new application?

I have enabled https on main domain and my applications are on subdomain so do I need to acquire certificate for subdomain also?

Also as mentioned in roadmap fb_sig parameter will be deprecated, so do I need to upgrade all my applications to Oauth 2.0 in order to make them work?

Please help me. Thanks in advance.

You must have ssl sertificate for your domain. It's not important where you buy or any other thing. facebook only look that if link is secure or not ( https)

So if you don' t have wildcard for your subdomains you have to buy wildcard for subdomains or ssl sertificate for each subdomain.