User defined fields in previous versions of the software were defined at the Plant level, now in v2016 they are defined at the Domain level. Therefore, if you have used the same UDF in two or more plants and used different names (captions), you must choose just one name for v2016. Also if the header in the browser is not defined in the Administration module it will not appear in the new Query Builder/EDE or in the browsers that were converted to EDEs. This applies to UDFs that appear in the browser fields. They must be defined in the Administration module. You can carry out these action pre or post upgrade.