So a month after Saurik said he was "almost done" we're going to get a working jailbreak with Cydia from two other developers.
Today 3uTools finds @FoxletFox and @iBSparkes shared some screenshots on Twitter which indicated Meridian + Substitute works with "some" Cydia packages! The developer explained he gets remote source functionality working, as well as the rest of the stack on his own iPhone. No support for pre/post scripts, however.
If the update going well, it should hopefully be available with the next Meridian update including libsubstitute.
We'll just have to assume he's over it. Please follow 3uTools for more updates.
Read here: Can I jailbreak my iPhone?