Today, Lao Zuo found an incompatibility when he helped a customer debug a website he moved from. It is finally found that the PHP version of our current system is too high (generally I prefer a higher version of PHP 7.4), and his theme is relatively old and can only be compatible with versions below PHP 7.0. I originally thought about changing a new theme, but enterprise users are accustomed to the existing theme, so they finally solved the problem of a function by modifying the code.

Since there are problems about PHP compatibility and version selection, Lao Zuo will talk about PHP version selection and stability of different PHP. For example, if we open our WordPress website, we will also be prompted to choose a higher PHP version in the background. At present, the official recommendation of WP is PHP 7.4+, but we may have upgraded to PHP 7.0-7.2 before.
First, select the PHP version according to program compatibility
Due to the CMS compatibility of the program we choose, as well as the compatibility of the theme. The feature may require the PHP version above or below. For example, I met a netizen who had to use PHP 5.6 to migrate an old website. If you can't, you can configure a PHP environment for her. (The pagoda panel was not used at that time)
Solution: If we choose WEB panel now, most of them are compatible with one server environment and use multiple PHP, and then use a separate PHP version for a single site.
Second, the need for program optimization and speed optimization
From our program compatibility, as well as our speed requirements and optimization requirements. At present, the highest PHP version is 8.0. Of course, it is really good after the experience of netizens, even better than 7.4. We can choose according to the actual compatibility. If compatible, we can choose the highest version. If it is safer, you can choose a secondary version. For example, Lao Zuo often uses PHP 7.4.
From the perspective of performance and tuning compatibility, 7.4+is also currently the mainstream requirement.
Therefore, when choosing which version of PHP is stable, we should try to choose a higher version. It must be advantageous to learn to adapt to the new version.