Okta Integration

Our Cyber team want to use SSO with Okta on our Gitlab Self hosted instance. I know this is supported in the latter version but we use 12.2.4, is it supported in that version.

Additionally the start of the help for SSO integration says to use https, currently we access our instance with a http addresss. Is https just best practice or will it not work with https. If we need https will it matter if it is a self signed certificate .