Standard PHP Library (SPL) extension is unavailable

The Standard PHP Library (SPL) is a collection of interfaces and classes that are meant to solve common problems.

As its name implies, the goal of the Standard PHP Library-or SPL, for short-is to provide a standard library of interfaces that allows developers to take full advantage of object-oriented programming in PHP 5. This library of interfaces creates a standard API for certain kinds of built-in functionality, allowing your classes to interact with the PHP engine in a much more seamless manner. The functionality it provides includes, for example, the ability to define how your objects will react when iterated over with foreach, advanced array access, file and directory access, and advanced SimpleXML object handling. The largest chunk of functionality that the SPL provides comes in the form of iterators.

SPL should be installed on your web host for Yoast SEO (Premium) to work.

If you see the following notice when installing Yoast SEO (Premium), your webhost does not have SPL installed or active on your domain.

The Standard PHP Library (SPL) extension seem to be unavailable. Please ask your web host to enable it.

Possible solutions

Have your host install/activate SPL for you.
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