QOpenGLShader::compile(Vertex): 0:11(19): error: `in' qualifier in declaration of `_qt_order' only valid for function parameters in GLSL 1.10

*** Problematic Vertex shader source code ***
#define lowp
#define mediump
#define highp
#line 1
attribute highp vec4 a_position;
attribute mediump vec2 a_texCoord;
uniform highp mat4 matrix;
varying mediump vec2 v_yaTexCoord;
varying mediump vec2 v_uvTexCoord;
uniform mediump vec2 yaTexScale;
uniform mediump vec2 yaTexOffset;
uniform mediump vec2 uvTexScale;
uniform mediump vec2 uvTexOffset;
in float _qt_order;
uniform float _qt_zRange;
void main() {
  gl_Position = matrix * a_position;
  v_yaTexCoord = a_texCoord * yaTexScale + yaTexOffset;
  v_uvTexCoord = a_texCoord * uvTexScale + uvTexOffset;
    gl_Position.z = (gl_Position.z * _qt_zRange + _qt_order) * gl_Position.w;
}
***