string fields replaced by text/keyword fields

[haarg]

https://www.elastic.co/guide/en/elasticsearch/reference/5.0/breaking_50_mapping_changes.html#_string_fields_replaced_by_textkeyword_fields

https://www.elastic.co/guide/en/elasticsearch/reference/5.0/breaking_50_mapping_changes.html#_literal_index_literal_property

[haarg]

This change can't be made on ES 2.4. It needs to happen along with the ES 5 upgrade.

[haarg]

Re-reading the ES change notes, string fields are still supported on Elasticsearch 5. They will automatically get converted to text or keyword fields as appropriate. So the path forward is probably to upgrade to ES 5, update our mappings in the code, then we'll be prepared to upgrade further.

The code that validates that mappings have been deployed properly will likely need some updates to account for this.