[Description] Changed type of the mustUnderstand attribute from restriction of boolean that only allowed 0 or 1 as lexical values to the standard boolean in the http://www.w3.org/2001/XMLSchema namespace. The lexical forms 0, 1, false, true are now allowed. [Class] 
Semantic
N a m e s p a c e
C l a r i f i c a t i o n
N a m e
S e m a n t i c
S t y l e
S y n t a x