Enabling SSL on hosted FeedPress feeds
FeedPress has support for SSL on RSS feeds. It is enabled by default on new feeds created after Dec 15, 2017. If your feed was created prior to the aforementioned date, you can turn SSL on. There are two ways to do this, depending on whether or not you're using a Custom Hostname.
Method 1 (feedpress.me feeds)
1. Go to Settings > Your Feed.
2. Enable the Enforce HTTPS delivery option.
Method 2 (Custom Hostnames)
1. Go to My Account > My Hostnames.
2. Enable the Enforce HTTPS delivery option.