Tonight at or around 9:00 pm EST, the State Department will release another batch of Hillary Clinton’s emails, including 150 (redacted) messages that the agency has “upgraded” to classified status.

The batch is expected to contain around 7000 messages total. In an effort to pad the landing for this latest release, State Department spokesman Mark Toner emphasized today during a press briefing that “the information we’ve upgraded was not marked classified at the time the emails were sent.”

More from the Wall Street Journal:

The latest set of emails is the fourth release of documents from Mrs. Clinton’s time in office. Previously, the State Department released records pertaining to the 2012 terrorist attack in Benghazi Libya, as well as thousands of pages of emails from her time in office.

The release of Mrs. Clinton’s records has been delayed by a controversy over the presence of classified information on her server—with multiple government agencies seemingly at odds over what should properly be considered classified.

Two inspectors general concluded that Mrs. Clinton’s inbox contained material that was classified when it was sent. The Clinton campaign and the State Department acknowledge that much of the material has been retroactively classified but insist that Mrs. Clinton didn’t send or receive anything with classification markings.

Many of the most sensitive and controversial of her emails are currently being reviewed as part of a multiagency process. State Department officials have noted that such referrals and consultations with other agencies don’t mean the emails will ultimately be deemed classified.

The FBI has headed up the investigation into how secure Clinton’s server was, and her campaign has been careful not to deviate too far away from the argument that any content received by Clinton would not have been marked as classified.

Still, investigators have made this a focal point in their questioning of those involved:

“It is hard to move classified documents into the non-classified system. You couldn’t move a document by mistake,” said Willes Lee, a former operations officer for the U.S. Army in Europe and former operations officer for the Joint Chiefs of Staff.

State Department spokesman Alec Gerlach confirmed the two systems don’t connect. “The classified and unclassified system are separate and you cannot email between the two,” Gerlach told Fox News.

The Clinton campaign adamantly denies any emails traversing Clinton’s homebrew server were marked classified at the time. The intelligence community inspector general says “potentially hundreds” of classified emails may be in the mix, but acknowledges at least some were not properly marked.

So if the Clinton denial is to be believed, individuals in her inner circle would have simply typed or scanned classified information into a non-classified system without regard for its contents. In this case, emails would have started in, and stayed in, the unclassified system — albeit improperly, based on the findings of the intelligence inspector general.

But if it turns out emails literally jumped from the classified to the non-classified system — something the State Department claims cannot happen — it would seem to point to Clinton’s staff going to great lengths to create a work-around to do so.

We’ll keep you updated as to the content of the newly released emails.