I know that lowercase_expanded_terms is valid in 2.x version and if the same is tried to execute in 8.9v gives "reason": "[query_string] query does not support [lowercase_expanded_terms]"
.
{
"size": 1000,
"query": {
"bool": {
"must": [
{
"query_string": {
"query": "*TEST*",
"fields": [
"elastic*"
],
"lowercase_expanded_terms": false // query does not support
}
}
]
}
}
}