Instead of using "unix://" you should just use "unix:":
$old = 'unix:///path/to/redis.sock';
$new = 'unix:/path/to/redis.sock';
The old format should be considered obsolete and will not be supported
starting from the next major release of Predis.
Meh
Falling back to a default timeout values should be done by the connection class
as it is an implementation detail that may vary depending on the backend.
Daniele Alessandri