XML Tool > Validation error

[Julianna]

I have 2 XML files with identical declaration,

<?xml version=“1.0” encoding=“UTF-8”?>
<standard dtd-version=“1.1” xmlns:xlink=“http://www.w3.org/1999/xlink” xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:tbx=“urn:iso:std:iso:30042:ed-1”>

one parsed, the other generated the following parsing error:

ERROR: Element ‘{urn:iso:std:iso:30042:ed-1}langSet’, attribute ‘{http://www.w3.org/XML/1998/namespace}lang’: ‘’ is not a valid value of the atomic type ‘xs:NMTOKEN’.

Using Notepad++ XML plugin - Validation tool.
Am I missing the latest XML plugin?

[chcg]

Last one seems to be https://sourceforge.net/projects/npp-plugins/files/XML Tools/Xml Tools 2.4.9 Unicode/, just 2.4.8 is available from the plugin manager currently.

Which version do you use? Or is it a different plugin?