Adding property to index type getting deprecation warning

Can someone help me to understand this warning message while adding adding property to the index type
PUT /mfrtestcase/_mapping/index
{
"properties": {
"mfrid": {
"type": "integer"
}
}
}

#! Deprecation: [types removal] Specifying types in put mapping requests is deprecated. To be compatible with 7.0, the mapping definition should not be nested under the type name, and the parameter include_type_name must be provided and set to false.
{
"acknowledged" : true
}