mod_s2s: to/from attributes are required on s2s stream headers. Set them to '' when not available. Fixes #468.
For full information on our dependencies, version requirements, and
where to find them, see http://prosody.im/doc/depends
If you have luarocks available on your platform, install the following:
- luaexpat
- luasocket
- luafilesystem
- luasec