Upgrade Guide

Migrating to v6

What's Changed

• Use the release.md PR template when creating release PRs with the workflow by @ajaynes-godaddy in #780
• Release v6.0.0 by @github-actions[bot] in #787
• Update POT file by @SVC81LjKClKSjX2JK-godaddy in #793
• Fix PHP 8.2 deprecation warnings caused by dynamic properties on the $order object by @iamdharmesh in #786
• PHP compatibility fixes by @peterwilsoncc in #789
• Explicitly mark parameters as nullable by @agibson-godaddy in #788

Full Changelog: 5.15.12...6.0.0