Apple has pushed an update to MRT bringing its version to 1.49 dated 12 September 2019.

Apple provides no details as to what changes this brings.

You can check whether this update has been installed by opening System Information via About This Mac, and selecting the Installations item under Software.

A full listing of security data file versions is given by SilentKnight, LockRattler and SystHist for El Capitan, Sierra, High Sierra, Mojave and Catalina, available from their product page. If your Mac has not yet installed this update, you can force an update using SilentKnight, LockRattler, or at the command line.

I have updated the reference pages here which are accessed directly from LockRattler 4.2 and later using its Check blog button.

I maintain lists of the current versions of security data files for Mojave on this page, High Sierra on this page, Sierra on this page, and El Capitan on this page.