XTEXT update: Since 5.1.1204, A-Shell has nominally supported TER15/HTS10 as well as TER18/HTS13, but experience has revealed problems with trying to support both versions in the same A-Shell executable. (One symptom was that the //XTEXT GDI directive wasn't working with TER18, but did work with TER15.) So as of this release, only TER18.DLL and HTS13.DLL are supported if using XTEXT.
On the plus side, there is a new feature which might possibly be useful (besides the hundreds of new features that we'll probably never use, and the hundreds of bug fixes that we may never appreciate): the ability to read (but not write) Word docx files. A new TXFF_DOCX symbol (7) has been defined in XTEXT.DEF, although for input (txc'docfmt'src), any value will work (other than TXFF_HTML), since the docx internal format is easily recognized.
There is another new DLL, TXML2.DLL, which in conjunction with the Windows DLL MSXML# (# = 2+), is required for the docx import feature.