Mapping type will be deprecated in version 7.0.0 and will be removed in 8.0. Instead, only the default _doc mapping type is used. If you have an index with multiple mapping types for logical grouping documents, the reindex operation must be performed in order for each document to have no mapping type. Recall that Elasticsearch 7.0 does not launch on nodes with an index created prior to 6.0. Therefore, you must first upgrade the old version to 6.x first.
You may perform the reindex operation to remove multiple mapping types in 6.x. Then, you can upgrade to 7.0. Assume that there is one cf_etf index with three mapping types including nyse, nasdaq, and cboe. To remove the mapping types, you may create a new index for each mapping type. Let's use the same name of the mapping type to create the corresponding index. After the indices...