Can I use one-letter names for weekdays?

Yes, here are the steps:

  1. Open your project. Click the arrow next to the Calendar language and choose Language Editor from the drop-down list.

    Select Language Editor

  2. Choose your language, in our case, it's English, and switch to the Weekday Names tab. Now type in the desired names for one of the shorter variants. We replaced every day name with one letter. Click Save to apply the changes.

    Type in new day names

  3. Now go to the Month Style and make sure that this variant is chosen for both Weekday Names and Weekend Names:

    Choose this variant for the grid

  4. Here is what you should get in the end:

    Example with one-letter day names