Fixing Invalid argument supplied for foreach() in .../extension.php on line 106

If you get error message :

Invalid argument supplied for foreach() in./administrator/components/com_installer/models/extension.php on line 106

So you can solve this by open its php file (extension.php) then

change the offending line from 

 $data = json_decode($item->manifest_cache); 

to 

 $data = unserialize($item->manifest_cache);