I have a 4.0 spine project . When I export json with 3.6 version.The curve infomation is lost.

Here is the json when export with version 4.0

"zhuzi4": {
        "translate": [
          {
            "time": 0.125,
            "x": -84.08,
            "y": -10.78,
            "curve": [
              0.307, -74.64, 0.477, -67.23, 0.307, -10.78, 0.477, -10.78
            ]
          },
          {
            "time": 0.625,
            "x": -62.73,
            "y": -10.78,
            "curve": [
              1.055, -51.65, 1.457, -43.65, 1.055, -10.78, 1.457, -10.78
            ]
          },
          {
            "time": 1.825,
            "x": -39.13,
            "y": -10.78,
            "curve": [
              1.884, -38.39, 1.942, -37.72, 1.884, -10.78, 1.942, -10.78
            ]
          },
          { "time": 2, "x": -37.15, "y": -10.78 }
        ],
        "scale": [
          { "x": 0.5, "y": 0.5, "curve": "stepped" },
          { "time": 0.125, "x": 0.5, "y": 0.5 },
          { "time": 0.3, "x": 1.04, "y": 1.04, "curve": "stepped" },
          { "time": 1.825, "x": 1.04, "y": 1.04 }
        ]
      }

Here is the json when export with version 3.6,the curve infomation is lost.

"zhuzi4": {
          "translate": [
            { "time": 0.125, "x": -84.08, "y": -10.78 },
            { "time": 0.625, "x": -62.73, "y": -10.78 },
            { "time": 1.825, "x": -39.13, "y": -10.78 },
            { "time": 2, "x": -37.15, "y": -10.78 }
          ],
          "scale": [
            { "x": 0.5, "y": 0.5, "curve": "stepped", "time": 0.0 },
            { "time": 0.125, "x": 0.5, "y": 0.5 },
            { "time": 0.3, "x": 1.04, "y": 1.04, "curve": "stepped" },
            { "time": 1.825, "x": 1.04, "y": 1.04 }
          ]
        }