Changing format of Date Time Picker custom fields

[Jakob KN]

Hi folks!

Currently in our Jira instance the system date fields (created, resolved, etc) and Date Picker custom fields are shown in the format "yyyy-MM-dd", while Date Time Picker custom fields are shown in "yy-MMM-dd HH:mm".

We'd like to use the same format in all field types, so under System > General Configuration > Advanced Settings, I've changed the value for jira.date.time.picker.java.format from 
"yy-MMM-dd HH:mm” to “yyyy-MM-dd HH:mm”.

However, when i use the basic search function with the calendar style date/time picker for the Date Time custom fields it throws an error stating:

Date value '23-Jun-6 09:07' for field 'Approval Date' is invalid. Valid formats include: 'yyyy/MM/dd HH:mm', 'yyyy-MM-dd HH:mm', 'yyyy/MM/dd', 'yyyy-MM-dd', or a period format e.g. '-5d', '4w 2d'

 
I'm assuming that the format of the calendar date/time picker needs to be changed as well, in order for it to work correctly, how is this done (if possible)?

Bonus question.
By the looks of it, saved filters which were created using the calendar picker before the format change, seems to still work after changing the format since the JQL value is not changed. It's yyyy-MM-dd HH:mm both before and after the change. 
Is there any potential issues that I've overlooked?

[Carla Ann Rowland]

The format for the jira instance for that field is default managed by the Jira instance administrators. One option would be using script runner behavior to change the display and format of the field.