Founders Brewing Co. has sent out Canadian flags to members of its Cadre club as a clue about its final Barrel-Aged Series release this year.

The flags seem to indicate that the final release of the series will be CBS—better known as Canadian Breakfast Stout—an imperial stout that is brewed with chocolate and a blend of coffees before being aged for over a year in spent bourbon barrels that were most recently aging maple syrup. The beer was first released in 22-ounce bottles in October of 2011, and was rereleased as a draft-only option exclusively in one-quarter-bbl kegs that were distributed to the brewery’s entire 32 state network in 2014.

According to a post on Founder’s website, the flags were sent as a clue to 1,000 of the brewery’s Cadre club, a membership club that is open to anyone who wishes to sign up. The post asks people who receive the package to post a photograph of the contents with the hashtag #FoundersBarrelAgedSeries, and promises that members of the club will find out what the release will be on on Oct. 30, “a full week before the rest of the public sees it.”

In addition, the Alcohol and Tobacco Tax and Trade Bureau (TTB) approved 750ml bottle labels of a new version of CBS in August, although every release in the series so far as also been packaged in 12-ounce bottles as well.

An email sent to the brewery for additional information was not immediately returned.