Hello, you should be able to create a refraction effect on v1.5.8r01+, but you'll have to set it up manually since we don't offer the port in the master node as in the Standard Surface shaders.
You can use our
Grab Screen Color node to access the new _CameraOpaqueTexture, which must be requested on the pipeline asset by toggling ON the Opaque Texture option over its General foldout.
Do note that this is only supported on SRP 4.0.0+, however, we're releasing an update tomorrow that adds support for SRP 2.0.0+.
Please let me know if this helps or if you come across any issues.