This is what I see in the admin by "update"!

Current version: 2.3.3

How to update

It's recommended to disable the forum while updating (uncheck "forum enabled" in the forum settings)
Download the latest version from mylittleforum.net
Unpack the script package, look for the according update file in the subfolder "update" and upload this file into the folder "update" on your server
Reload this page and the update file should appear below
Click on the file and follow the further instructions
After running the update you get a list of files and folders which have to be added or replaced
Clear the directory templates_c (delete all files in this dirctory) after you have added/replaced the files/folders
Available update file(s)

update_2.x-2.3.php

If I want to install the following update I get the following screen:

Error!
Error in line 258: This update file doesn't work with the current version.

I hope you now better understand what is going on!

Greetz, Dirk