WoltLab Suite Core 5.3 upgrades the bundled SCSS compiler from
leafo/scssphp 0.7.x to
With the updated composer package name the SCSS compiler also received updated namespaces.
WoltLab Suite Core adds a compatibility layer that maps the old namespace to the new namespace.
The classes themselves appear to be drop-in compatible.
Exceptions cannot be mapped using this compatibility layer, any
catch blocks catching a specific Exception within the
Leafo namespace will need to be adjusted.
More details can be found in the Pull Request WoltLab/WCF#3415.
WoltLab Suite Core 5.3 ships with a bundled version of Guzzle 6.
Going forward using Guzzle is the recommended way to perform HTTP requests.
\wcf\util\HTTPRequest class should no longer be used and transparently uses Guzzle under the hood.
\wcf\system\io\HttpFactory to retrieve a correctly configured
Please note that it is recommended to explicitely specify a
sink when making requests, due to a PHP / Guzzle bug.
Have a look at the implementation in WoltLab/WCF for an example.