Upgrading from 1.1.11 to 2.0 RC3

[ExiledDiclonius]

Hej guys/girls. I'm quite fresh SMF administrator. Atm my community is using SMF 1.1.11, but I would like to change it to 2.0 RC3. I would like to ask if there is easy way to upgrade it, or I must transfer mysql database (if possible). I was trying to find answer but without any effect 

[Kill Em All]

Welcome to SMF

See this guide on upgrading SMF:
Upgrading SMF

Always make sure to back up first though!!!

[ExiledDiclonius]

Thank You for this link. I was trying to do test upgrade acording to this tutorial, but I failed.

What I did.

1. I copied fresh installation files (1.1.11) to new folder on my serwer, and changed chmod of required files
2. I made new database, and imported database from my forum
3. I edited Settings.php, and everything worked fine.
4. I switched default theme to YaBB SE
5. I replaced 1.1.11 files with 2.0RC3 Upgrade files, and tried to start update.php
6. And than in 1st step i got info:

The upgrader was unable to find some crucial files.

Please make sure you uploaded all of the files included in the package, including the Themes, Sources, and other directories.

Click here to try again.

Dunno why that happend, especially when I instaled fresh 1.1.11, and all upgrade files. Anyone had this same problem?

EDIT: Do I need to change forum language to english before upgrading? I had PolishUTF8 language set as default, and I dont know if thet's the reason of my problems.

[Kill Em All]

You should make sure that you have the Polish UTF8 files there. so it should work, you can try changing it to english. You might not have uploaded all the files from the large upgrade package. Maybe try reuploading them?