A warning to commenters in the wee hours: Scheduled system work will probably block your ability to leave comments on Washington Post pages early Wednesday.

A migration of part of the Post’s technical infrastructure — specifically, the service that validates user logins — is scheduled to start around midnight, and users may be unable to log in to comment after it begins. Comments submitted before the work began should still be available to read.

We expect to have comments back at full steam later in the morning. We apologize for the inconvenience.