If you currently publish to Maven Central via oss.sonatype.org or s01.oss.sonatype.org, There should be NO IMPACT to your existing credentials and publishing processes. Both oss.sonatype.org and s01.oss.sonatype.org will continue to function after this date and into the foreseeable future.
What will change is the way publishers who use these hosts sign up for accounts and change their credentials. If you have any questions that are not addressed by the document linked above, please email central-support@sonatype.com