Slowlog differences between 8.17 and 7.17

Hello,

The request shown below works fine on Elasticsearch 7.17 but fails on 8.17 (also on 8.10 that I tried)

curl -X PUT "http://localhost:9200/my_index3" -H 'Content-Type: application/json' -d'
{
  "settings": {
    "number_of_shards": 1,
    "number_of_replicas": 1,
    "index.search.slowlog.level": "TRACE"
  }
}
'

On 7.17 -

{"acknowledged":true,"shards_acknowledged":false,"index":"my_index3"}%

On 8.17 -

{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"unknown setting [index.search.slowlog.level]"}],"type":"illegal_argument_exception","reason":"unknown setting [index.search.slowlog.level]"},"status":400}%

Is there anything special I need to be doing in 8.x for this?

Thank you

Apparently it changed a bit?

PUT /my-index-000001/_settings
{
  "index.search.slowlog.threshold.query.warn": "10s",
  "index.search.slowlog.threshold.query.info": "5s",
  "index.search.slowlog.threshold.query.debug": "2s",
  "index.search.slowlog.threshold.query.trace": "500ms",
  "index.search.slowlog.threshold.fetch.warn": "1s",
  "index.search.slowlog.threshold.fetch.info": "800ms",
  "index.search.slowlog.threshold.fetch.debug": "500ms",
  "index.search.slowlog.threshold.fetch.trace": "200ms"
}