Apple has pushed a single update overnight, to its malware removal tool MRT, bringing it to version 1.63, dated 25 June 2020.
Apple doesn’t release information about what this update adds or changes. Unusually, there is no accompanying update to XProtect on this occasion, and that remains at version 2123.
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 Catalina on this page, Mojave on this page, High Sierra on this page, Sierra on this page, and El Capitan on this page.