Hi @emcniece
The field_key instead of field_name issue is outlined in this doc http://www.advancedcustomfields.com/resources/functions/update_field/ and I will take a look at adding in functionality to step around this problem.
As for your solution, I’m glad you have found one. Just to confirm, when you upgraded from v4 to v4, you got multiple field’s with the same key?
Were these the newly created fields which got the same key? If so, how many fields got the same key?
