IIIF was originally not part of the funding for 2.0, but the developers were able to easily add it in as part of the rebuild of the image backend, as it was a part of Open Seadragon.
So, currently, DM 2.0 can ingest IIIF images from an online source, but while the foundation is there , the front interface for doing so is limited to single image ingestion from a specific info.json uri that is manually entered.
Obviously this is not how IIIF should work in DM - the goal is to have seamless batch and drag and drop and manifest consumption from the front end. We currently have a NEH ODH grant application submitted that would fund (among other features) the building the necessary IIIF consumption interface for DM 2.5 - if that is not funded, we'll be pursuing other funds to make this happen ASAP as a first priority for the next feature built in 2019 - it shouldn't be a lot of money or development hours to make this happen, regardless.