With this plugin you can set limit for no of active logins user can have..
Block new logins to the account, if maximum active logins found..
Settings - Set maximum no of active logins for user account...
In your WordPress admin panel, go to Plugins > New Plugin, search for LoggedIn and click.
Alternatively, download the plugin and upload the contents of loggedin zip to your plugins directory.
Maximum Active Logins option and select the number of active logins for user account...
If you would like to have additional feature for this plugin, let me know..
Scroll down to see the Maximum Active Logins..
Just copy+paste this code in your theme's functions php file or in custom plugin function f loggedin bypass users { Enter IDs to bypass $allowed users = array return in array } add filter.
Browse the code, check out SVN repository, or subscribe to the development log by RSS...
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