We released the Revision 4 update to SAM 2018.11.11 on May 21, 2019.
If you are using SAM 2018.11.11 r3 or earlier for Windows or Linux, you should see an automatic update window when you start SAM.
Automatic update does not work for Mac, so you should download a new installation file from the Download page to update on a Mac.
Best regards,
Paul.