Yes and no.
- The free version (demo) has all the original explicit scenes from the base game (up to Day 5). The scenes remain the same, and nothing has been changed or added.
- The paid version, however, includes everything found in the free version — as well as adding more content such as new scenes (ranging from flirty, suggestive, and explicit), additional dialogue lines/flavoured text, the option to penetrate Ren, more player choices, more customisation options, and (eventually) more CG art.
The DLC's Itch page and screenshots can probably explain it better than I can!