# Elasticsearch upgrade to 2.x and '.' issue in fieldname **URL:** \ **Category:** Elasticsearch\ **Created:** [March 12, 2016, 2:35am UTC](https://discuss.elastic.co/t/elasticsearch-upgrade-to-2-x-and-issue-in-fieldname/44218 "2016-03-12T02:35:37Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![adityanmishra](https://avatars.discourse-cdn.com/v4/letter/a/a587f6/32.png) [@adityanmishra](https://discuss.elastic.co/u/adityanmishra)\ **Post date:** [March 12, 2016, 2:35am UTC](https://discuss.elastic.co/t/elasticsearch-upgrade-to-2-x-and-issue-in-fieldname/44218/1 "2016-03-12T02:35:37Z")
Hi, I have a cluster which contains data from log files. The fields are dynamic. With the breaking change that '.' could not be part of field name. I could fix this issue for new data. But how should i update the existing fieldnames in mapping. Is their any utility which will take care of this. I think before making such a breaking change without any hack solution should have been their for making changes to existing data. Any suggestion will save my day ---
**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\ **Post date:** [March 12, 2016, 2:37am UTC](https://discuss.elastic.co/t/elasticsearch-upgrade-to-2-x-and-issue-in-fieldname/44218/2 "2016-03-12T02:37:15Z")
There's no way to do this within ES. I use Logstash to reindex - [https://gist.github.com/markwalkom/8a7201e3f6ea4354ae06](https://gist.github.com/markwalkom/8a7201e3f6ea4354ae06) ---
**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, 2017, 11:08pm UTC](https://discuss.elastic.co/t/elasticsearch-upgrade-to-2-x-and-issue-in-fieldname/44218/3 "2017-07-05T23:08:55Z")