To change the maximum frames per second (fps) in Sailfish OS (SFOS), you can follow these steps:

1. Open the Terminal app on your SFOS device.
2. Type the following command and press Enter:

   devel-su

   This command will grant you root access.
3. Enter the root password when prompted.
4. Type the following command to open the configuration file for the compositor:

   vi /etc/environment

   This command will open the file in the vi text editor. If you prefer a different text editor, you can replace "vi" with the name of your preferred editor.
5. Use the arrow keys to navigate to the line that starts with QT_QPA_EGLFS_SWAPINTERVAL. This line controls the maximum fps.
6. Press the i key on your keyboard to enter insert mode in vi.
7. Change the value after QT_QPA_EGLFS_SWAPINTERVAL= to your desired maximum fps. For example, if you want a maximum of 60 fps, change it to 1/60.
8. Press the Esc key on your keyboard to exit insert mode in vi.
9. Type :wq and press Enter to save the changes and exit vi.
10. Restart your SFOS device for the changes to take effect.

Please note that modifying system configuration files can have unintended consequences or may require technical knowledge. Make sure to proceed with caution and create a backup of any critical files before making changes.