I agree the stale information on the German language page is unfortunate.
But, R10 and R11 were deployed in June of 2024 so just over a year ago. All Let's Encrypt certs since then have used either R10 / R11 or E5 / E6 for ECDSA certs.
Would you explain more why this caused an error for you? Systems that "pin" an intermediate are highly discouraged.
To stay best informed you should subscribe to the API Announcement section of this forum. This is even more important for service providers. This ensures you see essential info such as this intermediate change: Deploying Let's Encrypt's New Issuance Chains
There are not many notices in that section so you will not be burdened with many emails.