Upgrading "system/database" folder breaks my application

[eluser]KeyStroke[/eluser]
Hi,

I'm still using an older version of the "system/database" folder files, because everytime I copy newer files to them, I start getting random database errors (like "unknown column" errors).

The files in the database folder are from a 1.6.x version (can't remember which one). Were there any major changes I should be aware of?