The DNC is shamelessly lying to the public.
This amendment was rejected by the committee 8-6.
The existing language on the DNC platform (which was not changed this year) simply says to "raise and index the minimum wage", without specifying the target number, or specifying what it is indexed to. It offers no mechanisms for the goal. This is basically just parroting Clinton's very own vague and handwavy "support" of $15 minimum wage that isn't actually a support. It's just about "Hey, if it comes to my desk I'll sign it, but otherwise states decide what they wanna do".
The DNC is straight up lying when they say their current platform supports $15 min wage. It just objectively does not. And they shot down an amendment that specifically was proposed for $15 min wage. So much for support.