This project uses a few different libraries (all open-source) and icons for different purposes, but the code and LetterMan itself is released in the "Public Domain" (no copyright).

If you redistribute this project you just shouldn't remove the "Licenses" folder and everythings fine.

Component License Description
JCalendar Artistic license I use the JCalendarCombo for date Selection
Zip4J Apache 2.0 Used for import & export (Backups)
H2 Database Own License Used for the main backend
Pdf-Renderer LGPL-2.1 Pdf printing
Handdrawn Icons CC-SA 3 Make the Letterman look neat :)