I use FreeBSD 10.4/amd64 and execute portdowngrade inside a jail. When I try to downgrade a port to a previous version I see this error message portdowngrade security/tor r449591 svn: E170013: Unable to connect to a repository at URL 'http://svn.freebsd.org/ports/head/security/tor' svn: E000043: Error running context: Protocol not supported Something went wrong with svn... Ensure you have the correct revision! The revision is correct. I was able to workaround this issue by modifying /usr/local/sbin/portdowngrade and changing the line : ${svnroot=http://svn.freebsd.org/ports/head} to : ${svnroot=svn://svn.freebsd.org/ports/head}
Thanks. I've used https as that's the recommended protocol.
A commit references this bug: Author: crees Date: Sun Oct 15 21:58:54 UTC 2017 New revision: 452167 URL: https://svnweb.freebsd.org/changeset/ports/452167 Log: Fix repo protocol While here, add LICENSE PR: ports/223035 Submitted by: Markus Koschany Changes: head/ports-mgmt/portdowngrade/Makefile head/ports-mgmt/portdowngrade/files/portdowngrade