DO NOT TEST ON A LIVE/PRODUCTION SITE but rather on a copy of a production site with the owners permission.
Directions on how to test and what to test can be found at https://docs.joomla.org/Pre-Release_Testing
Here's the link to the RC to install manually: https://github.com/joomla/joomla-cms/re ... 3.10.3-rc1
- All the normal things
- Install from URL and Install from Web functionality
- That Update Sites refresh and show updates
Thank you for helping Production test this next release of Joomla.