Probably TLS-supporting mail servers and OpenVPN clients as well. Atlassian JIRA is having issues as well, and they don't seem to be dynamically linked, either, so we have to wait on them.
Gmail had TLS heartbeat enabled as of an hour ago.
This is quite the nightmare.
Edit: I'm actually seeing conflicting reports, some places report TLS heartbeat support, but exploit scripts don't seem to recognize or be able to use it.
