Changes to the document type definition (DTD) files for 2016 MeSH 

We have made changes the MeSH DTD file in order to remove and add specific data fields to our XML release (see MeSH documentation).  
In addition the MeSH DTD files have been moved to the NLM Document Type Definitions (DTDs) for NLM Databases website and the names of the DTDs were changed 
to make them consistent with other NLM DTDs.

MeSH 2015 DTD filenames   MeSH 2016 DTD filenames
------------------------  ------------------------
desc2015.dtd	          nlmdescriptorrecordset_20160101.dtd
qual2015.dtd	          nlmqualifierrecordset_20160101.dtd
supp2015.dtd	          nlmsupplementalrecordset_20160101.dtd

Note that the new DTD file locations are now incorporated included in the distributed XML, so that users no longer need to download these files.