How to install

Klats goes on the teacher’s computer only. Nothing is installed on the students’ PCs: they open the test in a browser, and old Windows 7 PCs can use Chrome 109 or Firefox 115.

Installers for every system are on the front page.

Windows

Windows 10 or 11 will do.

1. Download Klats-Setup.exe and run it. If your computer has no internet, download the offline installer, Klats-Setup-Offline.exe, on another computer and bring it over on a USB stick.

2. Windows may show a blue “Windows protected your PC” window: it appears for new programs that few people have downloaded yet. Click “More info”, then “Run anyway”.

3. Windows asks whether to allow the app to make changes to the device. Click “Yes”: the installer sets Klats up for every user of the computer and opens the firewall so students can connect.

4. Go through the installer’s steps, and Klats appears in the Start menu.

Without admin rights

The installer asks for admin rights. If you don’t have them, ask the school’s IT person to:

• install Klats on your computer — the installer sets up the Windows firewall itself;
• if the school runs another firewall or antivirus, allow Klats incoming connections from the local network in it;
• check that your computer and the students’ PCs are on one network and can reach each other.

Mac

You need macOS 13 or newer, on a Mac with an Apple or Intel chip.

1. Download Klats.dmg and open it.

2. Drag Klats into the Applications folder.

3. Open Klats from Applications. The first time, macOS won’t open it, because the app isn’t signed with Apple. Close the message — just don’t move Klats to the Trash.

4. Open System Settings → Privacy & Security, scroll down and click “Open Anyway” next to the line about Klats.

5. Click “Open Anyway” once more and enter your Mac password. From then on Klats opens like any other app.

Linux

Klats runs on Ubuntu 24.04, Linux Mint 22, Debian 13, Fedora 40 and newer, on computers with a 64-bit Intel or AMD processor. Pick one of two files:

• The .deb package, for Ubuntu, Linux Mint and Debian. Open klats_amd64.deb in the software installer, or run sudo apt install ./klats_amd64.deb in a terminal. Klats appears in the app menu.
• The AppImage, for any of these systems, Fedora included, and it runs without installing. Allow Klats-x86_64.AppImage to run as a program (in its properties, or with chmod +x Klats-x86_64.AppImage) and run it.

How to uninstall Klats

• Windows. Remove Klats in Settings → Apps, like any other program. At the end the uninstaller asks “Also delete my tests and results?” Answer “Yes”, and it deletes the data folder of the user who uninstalls, %AppData%\Klats: all tests, classes, results and settings. “No” is the default: the data stays, and Klats finds it again if you reinstall. Backups saved in other folders are never deleted.
• Mac. Drag Klats from Applications to the Trash. The data stays in ~/Library/Application Support/Klats; delete that folder if you no longer need it.
• Linux. Remove the package with sudo apt remove klats, and the AppImage like any file. The data stays in ~/.local/share/klats.

Next: the first lesson →