Moving tickets from classic to next gen project doesn't fill custom fields

[Mike Slivka]

We have occasion to move tickets from a classic project to a next gen project, but there is a custom field we added to the source and target issue types which doesn't fill. The field name is the same in both the projects. 

Is there a way to get custom fields to migrate between project types? 

[Alexey Matveev]

Hello,

The only way I found to migrate custom fields is to export all data from a next-gen project to a csv file, then create new custom fields and modify your csv file so that values in the custom fields in the next-gen project would be named as newly created custom field. Then you can upload the csv file to Jira. 

I would strongly advise you to try it first in a test environment.