It is often recommended to uninstall the previous version of Arnold to avoid "ghost" plugins in the C4D bridge.
| Cinema 4D Version | Compatibility with Arnold 4.4.0 | Notes | |------------------|--------------------------------|-------| | (late 2019) | Full support | Requires C4DtoA 2.6.x or 3.0.x bridge. | | R22 (late 2020) | Full support | Short-lived version, but solid. | | R23 (late 2020) | Full support | Last version with legacy UI (pre-S26). | | R (R25 / R26 / R2023) | Partial legacy support | "R" usually means R25+ with updated bridge plugins ported back. |