As you've seen, Shopify has started removing all HTTP on the platform. Next up after webhooks are app proxies!
Here is what the timeline looks like:
On July 1st 2018, newly created apps will no longer be able to create HTTP proxies.
On September 1st 2018, all apps will no longer be able to create HTTP proxies.
On January 1st 2019, all remaining HTTP proxies will be removed.
As always feel free to comment with and questions or concerns.
Shopify Apps Team