Hi,
The download link to the 7.11->7.12 patch is broken over here: Upgrade SuiteCRM - SuiteCRM
https://suitecrm.com/files/147/SuiteCRM-7.12/576/SuiteCRM-Upgrade-7.11.x-to-7.12.1.zip
The file seems to be missing, and you’ll get redirected to SuiteCRM - the open source alternative to SalesForce, Microsoft Dynamics and SugarCRM Professional
The file can though be downloaded from sourceforge
https://sourceforge.net/projects/suitecrm/files/upgrades/