Elasticsearch synonyms for index analyzer

I am trying to add synonyms filter to my Elasticsearch analyzer. Precisely, I need to add synonyms to the index analyzer because I use fuzzy search and want it it recongnize typos in synonyms as well.

But when I try to create index alanyzer:

"filter": {
  "synonyms": {
    "type": "synonym_graph",
    "synonyms": [
        ...
    ]
  }
}

"index_analyzer": {
  "tokenizer": "standard",
  "filter": ["lowercase", "synonyms", "edge_ngram"]
}

and then specify it as index analyzer for a field:

"text" : {
  "type" : "text",
  "analyzer": "index_analyzer",
  "search_analyzer": "search_analyzer"
}

I get an error:

{
  "error" : {
    "root_cause" : [
      {
        "type" : "mapper_exception",
        "reason" : "analyzer [index_analyzer] contains filters [synonyms] that are not allowed to run in index time mode."
      }
    ],
    "type" : "mapper_parsing_exception",
    "reason" : "Failed to parse mapping [_doc]: analyzer [index_analyzer] contains filters [synonyms] that are not allowed to run in index time mode.",
    "caused_by" : {
      "type" : "mapper_exception",
      "reason" : "analyzer [index_analyzer] contains filters [synonyms] that are not allowed to run in index time mode."
    }
  },
  "status" : 400
}

Though Elasticsearch documentation says:

You can specify the analyzer that contains your synonyms set as a search time analyzer or as an index time analyzer.

What am I doing wrong? Elastisearch version is 7.17.5.

You can specify the analyzer that contains your synonyms set as a search time analyzer or as an index time analyzer.

The above sentence is accurate for ES version v8.10 and later. You can't use index time analyzer on version v7.17

https://www.elastic.co/guide/en/elasticsearch/reference/current/release-notes-8.10.0.html