# Upgrade Logstash : mutate filter is not working well
**URL:** https://discuss.elastic.co/t/upgrade-logstash-mutate-filter-is-not-working-well/28090
**Category:** Logstash
**Created:** [August 26, 2015, 10:05am UTC](https://discuss.elastic.co/t/upgrade-logstash-mutate-filter-is-not-working-well/28090 "2015-08-26T10:05:52Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Hornov](https://discuss.elastic.co/u/Hornov)
#### Post date: [August 26, 2015, 10:05am UTC](https://discuss.elastic.co/t/upgrade-logstash-mutate-filter-is-not-working-well/28090/1 "2015-08-26T10:05:52Z")
Following the logstash migrating from 1.4.2 version to 1.5.3 version when I do an uppercase in the mutate filter on a field ending with numeric value the field becomes nil.
Yet, before that worked.
How can I fix it ?
My logstash config :
filter {
mutate {
convert =\> ["my\_field","string"]
uppercase =\> ["my\_field"]
...
---
### Author:  [@Hornov](https://discuss.elastic.co/u/Hornov)
#### Post date: [August 26, 2015, 12:50pm UTC](https://discuss.elastic.co/t/upgrade-logstash-mutate-filter-is-not-working-well/28090/2 "2015-08-26T12:50:18Z")
That's the same thing with lowercase and kibana says to me : objects in arrays are not well supported.
Although this is just a simple string not an array
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### Author:  [@Hornov](https://discuss.elastic.co/u/Hornov)
#### Post date: [September 10, 2015, 2:50pm UTC](https://discuss.elastic.co/t/upgrade-logstash-mutate-filter-is-not-working-well/28090/3 "2015-09-10T14:50:27Z")
Nobody has encountered this problem ?
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### Author:  [@James\_Tang](https://discuss.elastic.co/u/James_Tang)
#### Post date: [October 27, 2015, 2:26pm UTC](https://discuss.elastic.co/t/upgrade-logstash-mutate-filter-is-not-working-well/28090/4 "2015-10-27T14:26:35Z")
@Hornov, Facing the issue now. Pretty upset. 😡 The behavior is inconsistent.
In the filter, I grok first. Follow by mutate. It will work. But randomly mutate.uppercase=\> [field] will cause that field to be null/nil whatever. It is corrupting my data!
I am running on windows and linux.
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### Author:  [@James\_Tang](https://discuss.elastic.co/u/James_Tang)
#### Post date: [October 27, 2015, 2:53pm UTC](https://discuss.elastic.co/t/upgrade-logstash-mutate-filter-is-not-working-well/28090/5 "2015-10-27T14:53:34Z")
>
Ok. Some digging and found this piece of information. So just need to update the plugin
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 5:25am UTC](https://discuss.elastic.co/t/upgrade-logstash-mutate-filter-is-not-working-well/28090/6 "2017-07-06T05:25:14Z")