Error: can not write type [class java.time.LocalDate] - Elasticsearch v8.10

[Abhishek (Abhishek Pratap Singh)]

Hi Everyone,
I have recently upgraded from es 5.6 to es 8.10.
Following script field is working fine in es5.6

"script_fields": {
      "customDate": {
      "script": {
         "inline": "def i ; if(params._source.customDate == null && params._source.remainder != null ) {
				def cd = params._source.exDate;
				def df = DateTimeFormatter.ofPattern(\"MM/dd/yyyy\"); 
				def localDate =  LocalDate.parse(cd,df); 
				if(doc['remainderType'].value=='day') { i = localDate.minusDays(doc['remainder'].value); } 
				else if(doc['remainderType'].value=='month') { i = localDate.minusMonths(doc['remainder'].value); } 
				else if(doc['remainderType'].value=='year') { i = localDate.minusYears(doc['remainder'].value); } 
				} 
			    else if(params._source.customDate != null) {
				i = params._source.customDate 
				}
		  return i"
      }
   }
}

field mapping:

"customDate": {
          "type": "date",
          "format": "MM/dd/yyyy"
        },
"remainder": {
          "type": "long"
        },
"exDate": {
          "type": "date",
          "format": "MM/dd/yyyy",
          "fields": {
            "keyword": {
              "type": "keyword"
            }
          }
        }
"remainderType": {
          "type": "keyword"
        }

In es 8.10, it gives following error (response from kibana dev console):

#! [script][88:20] Deprecated field [inline] used, expected [source] instead
{
  "error": {
    "root_cause": [
      {
        "type": "illegal_argument_exception",
        "reason": "can not write type [class java.time.LocalDate]"
      }
    ],
    "type": "search_phase_execution_exception",
    "reason": "all shards failed",
    "phase": "query",
    "grouped": true,
    "failed_shards": [
      {
        "shard": 0,
        "index": "index_v1",
        "node": "node-A",
        "reason": {
          "type": "illegal_argument_exception",
          "reason": "can not write type [class java.time.LocalDate]"
        }
      }
    ],
    "caused_by": {
      "type": "illegal_argument_exception",
      "reason": "can not write type [class java.time.LocalDate]",
      "caused_by": {
        "type": "illegal_argument_exception",
        "reason": "can not write type [class java.time.LocalDate]"
      }
    }
  },
  "status": 400
}

Thanks in advance.