This free ClassicPress plugin allows administrators to disable user accounts, preventing users from logging in and logging them out if they are already logged in.
You can customise the meta key that the disabled status is stored under in the usermeta table.
You can also decide whether anyone with the “edit_users” capability can disable/enable users, or whether only admins (with the “manage_options” capability) can.
To install the plugin, go to the admin plugins page, click the ‘Add New’ button, then click the ‘Upload Plugin’ button and upload the zip file you downloaded.
Even though this plugin is not in the WordPress plugin repository, future updates will be shown on the admin plugins page when available. Please note that the plugin must currently be active in order to check for updates.