{"action":"opened","issue":{"url":"https://api.github.com/repos/smartdevicelink/sdl_core/issues/17","labels_url":"https://api.github.com/repos/smartdevicelink/sdl_core/issues/17/labels{/name}","comments_url":"https://api.github.com/repos/smartdevicelink/sdl_core/issues/17/comments","events_url":"https://api.github.com/repos/smartdevicelink/sdl_core/issues/17/events","html_url":"https://github.com/smartdevicelink/sdl_core/issues/17","id":55291017,"number":17,"title":"[Spec] The version can never be increased beyond 15, or backward compatibility is broken","user":{"login":"joeljfischer","id":1767063,"avatar_url":"https://avatars.githubusercontent.com/u/1767063?v=3","gravatar_id":"","url":"https://api.github.com/users/joeljfischer","html_url":"https://github.com/joeljfischer","followers_url":"https://api.github.com/users/joeljfischer/followers","following_url":"https://api.github.com/users/joeljfischer/following{/other_user}","gists_url":"https://api.github.com/users/joeljfischer/gists{/gist_id}","starred_url":"https://api.github.com/users/joeljfischer/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/joeljfischer/subscriptions","organizations_url":"https://api.github.com/users/joeljfischer/orgs","repos_url":"https://api.github.com/users/joeljfischer/repos","events_url":"https://api.github.com/users/joeljfischer/events{/privacy}","received_events_url":"https://api.github.com/users/joeljfischer/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-01-23T15:04:48Z","updated_at":"2015-01-23T15:04:48Z","closed_at":null,"body":"We discovered #16 when we were discussing this issue.\r\n\r\nWe can never actually increase the version beyond 15 because of how backward compatibility works. If we attempt to, we would run into an issue with the Head Unit sending it's max version back as part of a StartSessionACK. If the head unit sends a new style ACK with a larger version byte, then previous versions of the mobile library will not be able to read it. If it sends an old style ACK then that version can never be increased beyond 0x0F."}}