Bug in Configuration/FlexForms/Demand.xml since TYPO3 13

[CMS-Internetsolutions]

Bug Report

Prerequisites

Bug only on TYPO3 13.
Tested in TYPO3 13.4 and 12.4.24 and Extension blog v13.0.0

Description

Flexform Fields in Configuration/FlexForms/Demand.xml

[Description of the bug]
See attached Screenshot before eand after remove TCEforms tag in Demand.xml file.

Steps to Reproduce

After change the Demand.xml file, remove TCEforms tag it works again.
Hint:
https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/ApiOverview/FlexForms/Index.html
Changed in version 13.0
The superfluous tag TCEforms was removed and is not evaluated anymore. Its sole purpose was to wrap real TCA definitions. The TCEforms tags must be removed upon dropping TYPO3 v11 support.

Versions

After fix in file:

Before fix in file:

Many thanks and a Merry Christmas and a Happy New Year!
Thanks to the TYPO3 team!!
Eric

[jacobsenj]

This is due to the deprecation of TCEforms in flexform from TYPO3 12.0 (https://docs.typo3.org/c/typo3/cms-core/main/en-us/Changelog/12.0/Deprecation-97126-TCEformsRemovedInFlexForm.html) which has now been removed in TYPO3 13.

All TCEforms tags need to be removed from the flexform xml which also drops support for TYPO3 11 and earlier.

https://github.com/jacobsenj/blog/blob/feature/TYPO3-13.4.x/Configuration/FlexForms/Demand.xml