Image I/O plug-ins set metadata boolean attributes to "true" or "false"
According to the native and standard stream and image metadata specifications these should be "TRUE" or "FALSE", respectively.

Do a case-insensitive comparison when testing the value of a boolean attribute.

Not a showstopper.
  xxxxx@xxxxx   2004-08-05
Relax the implementation and the specification to be more accommodating.

  Clarify specification of the boolean data type in IIOMetadataFormat
  class to explicitly declare the set of allowed names for the values for
  boolean attributes.

  Change the implementation to consistently emit uppercase literal "TRUE" 
  instead of lowercase "true", and "FALSE" instead of "false" for all metadata
  boolean attributes.

  In order to help minimise backward incompatibility, the implementations
  that previously accepted only lower case, will now accept both lowercase and
  uppercase "true" and "false" values. This will accommodate the case where
  metadata was constructed to satisfy the previous lowercase behavior.
Posted Date : 2009-01-13 14:35:08.0