Old core files, which have no use and must be deleted, result from WordPress upgrades.
When WordPress gets upgraded, these files become useless but they are stored on the server.
You never know whether these core files exist unless you look for them specifically.
One way to discover whether your WordPress installation has these files on the server is by using the Old Core Files plugin to your benefits. Deleting old core files is important in order to prevent your site from security threats.
Let’s see how to install the plugin –
1. Log in to your WordPress dashboard.
2. Go to Plugins in the left navigation, and click on Add New.
3. Type Old Core Files in the search box and hit Search Plugins.
4. Once found, click the corresponding Install Now button.
5. Click the OK button to start installtion.
6. After the plugin has installed, click the corresponding Activate Plugin link.
Now that the Old Core Files plugin has been activated, it’s time to view the list of all the old core files that are not required.
Go to Plugins in the left navigation again, and click the Installed Plugins function. On the next page, locate the Old Core Files plugin and click the Settings link corresponding to the plugin.
In the plugin’s Settings section, you’ll be able to view the list of old or existing core files.
Once you have the list at hand, you can have them deleted via FTP.