2
           
            
                
     
    
    This is from 2.0.14 readme:
 Upgrading from any XOOPS version between 2.0.10 and 2.0.13.2 
 
   1. Copy the content of the htdocs/ folder except mainfile.php over your existing installation. 
   2. Delete the following folders and files: 
          * class/smarty/core 
          * class/smarty/plugins/resource.db.php 
   3. Empty the templates_c folder (except index.html) 
   4. Upload the upgrade folder to your site 
   5. Ensure the server can write to mainfile.php 
   6. Login using an administrator account 
   7. Access <your.site.url>/upgrade/ using your browser, and follow the instructions 
   8. Write-protect mainfile.php again 
   9. Remove the upgrade folder after use  
So you should upgrade to 2.0.10
2.0.10 -> 2.0.14
2.0.14 -> 2.0.16
Be shure to make backups at any step.