Correct.
Windows XP was released August 2001, making it 13 years old, and support ended April 2014.
Windows Server 2003 was released April 2003, making it 11 years old, and support ends July 2015.
The fact that Windows XP and Server 2003 do not support .Net 4.5 is not an issue with SambaPOS; it is an issue with Microsoft.
P.S. I love XP as much as the next person, and I still have a Server running 2003, but time moves on, and so should we all… especially when you’re running something as mission-critical as a POS.