Why is my Fade Post Processing effect no longer working?

I had a fade effect on my camera to fade in/out. When I was in Unity 5.5 it worked fine, but now that I upgraded to 5.6 it no longer works. Was something changed with how post processing works now? Any ideas and suggestions would be appreciated. Here is the code I am using: public class Fade : MonoBehaviour {

     [SerializeField]
     private Color _colour = Color.white;
 
     [SerializeField]
     [Range(0, 10)]
     private float _fadeSpeed;
 
     [SerializeField]
     [Range(0, 1)]
     private float _alpha;
 
     [SerializeField]
     private Material _material;
 
     private void OnRenderImage(RenderTexture source, RenderTexture destination)
     {
         _material.SetColor("_Color", _colour);
         _material.SetFloat("_Alpha", _alpha);
         Graphics.Blit(source, destination, _material);
     }
 
 }
 
 
 Shader "Post Processing/Fade" 
 {
     Properties{
         _Color("Color", Color) = (1,1,1,1)
         _MainTex("Texture", 2D) = "white" { }
     _Alpha("Alpha", Range(0,1)) = 1
     }
         SubShader{
         LOD 200
         Tags
     {
         //"Queue" = "Transparent"
         //"RenderType" = "Transparent"
     }
 
     Pass{
         Blend SrcAlpha OneMinusSrcAlpha
 
 
         CGPROGRAM
 #pragma vertex vert
 #pragma fragment frag
 
 #include "UnityCG.cginc"
 
         float4 _Color;
     sampler2D _MainTex;
     float _Alpha;
 
     struct v2f {
         float4  pos : SV_POSITION;
         float2  uv : TEXCOORD0;
     };
 
     float4 _MainTex_ST;
 
     v2f vert(appdata_base v)
     {
         v2f o;
         o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
         o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
         return o;
     }
 
     half4 frag(v2f i) : COLOR
     {
         half4 texcol = tex2D(_MainTex, i.uv);
 
         texcol = half4(_Color.rgb, _Alpha);
         //texcol.rgb = dot(texcol.rgb, float3(0.3, 0.59, 0.11));
 
         return texcol;
     }
         ENDCG
 
     }
     }
         Fallback "Diffuse"
 }