Important: The FlexForm data structures moved 

Description 

Version 2.x shipped the FlexForm data structure of the Partner List twice, as Configuration/FlexForms/Core12/ListSettings.xml and Configuration/FlexForms/Core13/ListSettings.xml, and picked one by the TYPO3 major version. The Partner Map used the same file.

With TYPO3 v12 no longer supported, see Breaking: Removed TYPO3 v12 support, each content element has one file of its own:

Content element Data structure
Partner List Configuration/FlexForms/ListSettings.xml
Partner Map Configuration/FlexForms/MapSettings.xml

The directories Configuration/FlexForms/Core12/ and Configuration/FlexForms/Core13/ are gone. The fields both elements had keep their sheet and their names, so the stored settings of existing content elements and page TSconfig that addresses them keep working. The new fields are described in Feature: The partner list can be paginated and Feature: The partner map is configurable per site.

Impact 

Code or configuration of a site that names one of the former files by path, in TCA of its own or in a copy of the data structure, names a file that no longer exists.

Migration 

Name the new file of the element instead. A map names EXT:academic_partners/Configuration/FlexForms/MapSettings.xml, not the file of the list: the fields of the map are only in its own file.