# 6.8 to 7.x - This index has date fields with deprecated formats **URL:** \ **Category:** Elasticsearch\ **Created:** [March 4, 2022, 4:42pm UTC](https://discuss.elastic.co/t/6-8-to-7-x-this-index-has-date-fields-with-deprecated-formats/298865 "2022-03-04T16:42:03Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![MatthiasLenhardt](https://avatars.discourse-cdn.com/v4/letter/m/a9adbd/32.png) [@MatthiasLenhardt](https://discuss.elastic.co/u/MatthiasLenhardt)\ **Post date:** [March 4, 2022, 4:42pm UTC](https://discuss.elastic.co/t/6-8-to-7-x-this-index-has-date-fields-with-deprecated-formats/298865/1 "2022-03-04T16:42:03Z")
Hi, we are planing to upgrade Elasticsearch from 6.8 to 7.x. Kibana " 7.0 Upgrade Assistant" tells us for some indices "Date field format uses patterns which may change meaning in 7.0", e.g.: This index has date fields with deprecated formats: [[type: message, field: gl2\_processing\_timestamp, format: yyyy-MM-dd HH:mm:ss.SSS, suggestion: 'y' year should be replaced with 'u'. Use 'y' for year-of-era.], [type: message, field: gl2\_receive\_timestamp, format: yyyy-MM-dd HH:mm:ss.SSS, suggestion: 'y' year should be replaced with 'u'. Use 'y' for year-of-era.], [type: message, field: timestamp, format: yyyy-MM-dd HH:mm:ss.SSS, suggestion: 'y' year should be replaced with 'u'. Use 'y' for year-of-era.]]. Prefix your date format with '8' to use the new specifier.` Indeed I see these formats in the index mapping and the mapping templates, but to be honest, I have no idea, who to handle this. Any help is appreciated. Thanks in advance! Matthias ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [April 1, 2022, 4:43pm UTC](https://discuss.elastic.co/t/6-8-to-7-x-this-index-has-date-fields-with-deprecated-formats/298865/2 "2022-04-01T16:43:00Z")
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