I found something wrong about shared prototype after framer studio latest update. After latest update I can't download or open the shared prototype using the old framer library.
For example, old shared prototype (http://share.framerjs.com/0qw309wo2yb9/) does not support download button. New shared prototype(http://share.framerjs.com/5ilbpnqfvzka/) supports download button.
After comparison new share page and old page, I found a way to open it. Open the scheme “framer://share.framerjs.com/download/sdi6ib57zoe3/project.zip” in the Safari then Framer Studio will download the prototype.
All you need to do is copy the old prototype id something like "0qw309wo2yb9" to framer://share.framerjs.com/download/ "Copy the old prototype id here (not include quotation)"/project.zip.