WordPress import database error Unknown collation: utf8mb4_unicode_520_ci solution

When importing a database into the local environment today, the prompt #1273 – Unknown collation: ‘utf8mb4_unicode_520_ci’ is incorrect, as shown below:

The reason is that the difference in the database version causes the wordpress database to be coded in different ways. In MySQL 5.6 and above, when WordPress 4.6 and above are installed, the default encoding is utf8mb4_unicode_520_ci, but MySQL 5.5 and below does not support utf8mb4_unicode_520_ci, so it cannot be imported.

The processing method is to use a code editor such as sublime text, open the .sql database, and then batch search and replace all utf8mb4_unicode_520_ci to utf8mb4_unicode_ci, save and upload.

Downgrade WordPress to Old Versions Online with WP Downgrade

We all know that whenever WordPress has new books, we can update them one-click in the background. But sometimes, our theme or plug-in may not be compatible with the new version of WP. At this time, if we want to downgrade to the previous old version, what should we do? Take a look below.

Important note: Regardless of upgrade or downgrade, before operating, please be sure to back up your website data, especially the website database, just in case!

Online downgrade

The so-called online downgrade is the same as updating the new version with a key. However, we need to use the WP Downgrade plug-in to implement it, so we must first install and enable WP Downgrade. Then access the Settings – WP Downgrade menu and set the version we want to downgrade.

For example, if you want to demote from 4.7 down to 4.6.1, you can fill in 4.6.1 according to the figure below, and then click “Save Changes”:

You can visit this page to check the WordPress version information: https://wordpress.org/download/release-archive/

Pay attention to the red information at the bottom of the figure: 4.6.1 The download link does not exist for Simplified Chinese. At this time, we can access Settings – General, change the language to English, and save it:

Then visit the Dashboard – Updates interface and click on “RE-install Now” to start the reinstallation of the old version specified:

Don’t worry about language problems. After installing the original English version, our language pack files will not be lost!

After installation, we will visit the Settings – General interface and change the language to Simplified Chinese. After saving, you can see the previous Simplified Chinese interface!

Well, that’s it! If everything is OK, you can uninstall the WP Downgrade plugin.