ETS 6.2.0 - ERROR - Unsupported namespace: 'http://knx.org/xml/project/22'

Today I updated ETS6 to the latest version, because there was an update available.

The last time I did use ETS6 was December 20, 2023. At that time ETS6 was up-to-date.

ETS Version: ETS 6.2.0 (Build 7181)
Master Data: v20
Interface: v68
Plugin Info: v1
Online Catalog: 04/03/2024

When I open my project I get an error;

Error
An internal error occurred.
Unsupported namespace: 'http://knx.org/xml/project/22'

After I hit the 'OK' button it says;

ETS - Error
An internal error occurred.
Failed to open project with id 'P-05DC'.

I did tried to replace the knx_master.xml file in C:\Program Files (x86)\ETS6 folder with the version from https://update.knx.org/data/XML/project-20/knx_master.xml (since it says Master Data v20). After that i did also tried project-21, 22 and 23. But all didn't fix the error.

I just updated to the latest version (as I always do when one is available), but now i can not open my Project anymore?!

Has anyone an idea how I can fix this problem?