This is a non-security release, that primarily includes updates to allow Panopoly to work with PHP 7.2, including the update to Drupal core 7.61, some contrib module updates, and additional patches.
But there's also a bunch of minor bug fixes and feature additions, that have been hanging around in the issue queue for some time. :-)
For more information, please see the full release notes:
https://www.drupal.org/project/panopoly/releases/7.x-1.58
Remember: you have to update the WHOLE profile - not just the individual panopoly_* modules! Otherwise, you'll be missing important module updates/patches, and it isn't guarenteed to work.
For full instructions on how to upgrade, please see the Upgrading Panopoly guide! (We invite you to help us improve it as well.)
And, of course, you can find links to download, documentation and report problems on the Panopoly project page:
https://drupal.org/project/panopoly
Thanks!