Short-URL 3.1 Update

Short-URL 3.1 Update 🌐🔗

Before talking about the content:

This is a very small update (for some people) because there is only one update. But this update will affect all themes ⚠️

Content:

1. Split logic PHP: Part of the code in index.php is split into two files, namely {Theme}/UI/index-return-ok.php and {Theme}/UI/index-return-error.php ✂️💻

Postscript:

This version is not compatible with the old version of Theme. ⚠️

Full Changelog: surl3...surl3.1