# Unable to update mappings for Date fields in order to prepare for migration from 6.x to 7.x **URL:** \ **Category:** Elasticsearch\ **Created:** [June 7, 2021, 11:04am UTC](https://discuss.elastic.co/t/unable-to-update-mappings-for-date-fields-in-order-to-prepare-for-migration-from-6-x-to-7-x/275138 "2021-06-07T11:04:32Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Raja\_Kolluri](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/raja_kolluri/32/89920_2.png) [@Raja\_Kolluri](https://discuss.elastic.co/u/Raja_Kolluri)\ **Post date:** [June 7, 2021, 11:04am UTC](https://discuss.elastic.co/t/unable-to-update-mappings-for-date-fields-in-order-to-prepare-for-migration-from-6-x-to-7-x/275138/1 "2021-06-07T11:04:32Z")
Hi, i am trying to migrate Elasticsearch from 6.x to 7.x version. "Indices" Tab in Upgrade Assistant 7.0 page in Kibana shows below warning message for most of my indices, > This index has date fields with deprecated formats: [[type: pipeline, field: Date, format: EEE MMM d HH:mm:ss yyyy Z, suggestion: 'y' year should be replaced with 'u'. Use 'y' for year-of-era.; 'Z' time zone offset/id fails when parsing 'Z' for Zulu timezone. Consider using 'X'.] 1. i have created one temporary index name - xxxx-new with mapping format as "EEE MMM d HH:mm:ss 8yyyy Z". change here is prefixed 8 to yyyy 2. i have tried to reindex one index-xxxx in to new index xxxx-new but reindex operation failed as > Invalid format: "Thu May 23 01:00:00 2019 -0400" is malformed at " 2019 -0400 Please suggest a solution! Thanks, Raja ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 5, 2021, 11:05am UTC](https://discuss.elastic.co/t/unable-to-update-mappings-for-date-fields-in-order-to-prepare-for-migration-from-6-x-to-7-x/275138/2 "2021-07-05T11:05:08Z")
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