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.