Did it happen because of the version update or was it because of the upgrade to Cloud 3? In any case both URLs will work, the old URL will automatically redirect to the new one.
If there’s a new implementation required, the use the new URL. Otherwise you can continue to use the old URL, if its too much work to change to the new one and test everything.
When an endpoint URL changes after an upgrade, you should typically update the consumer applications to use the new URL. The new URL is likely to align with the changes made in the upgraded version and may offer improved functionality, security, or performance.
There will be no impact in the application and service