Version 1.9.0 marked a milestone by introducing robust support for first-person model rendering. In older versions, a custom player model might disappear or clip incorrectly when the player entered first-person mode, or the custom animations would conflict with the vanilla "bobbing" of the camera. The 1.9.0 update introduced the architecture necessary to modify the first-person arm model without breaking the camera logic. Furthermore, this version brought updates to the internal math parser, allowing for smoother easing and more complex procedural animations. Therefore, installing this version or later is essential for any add-on that aims to provide a polished, professional visual experience.