In my view , office 2016 upgrade has nothing to do with CA Devtest solution. and about spreadsheet /excel usages it depend on what library support to read/write data into and/or from spreadsheet. like using Apache POI or JXL, libraries etc. they support scripting language (groovy, java script ) java etc.
Try Read / Write Excel file (.xlsx) using Apache POI using any editor and it should work in Devtest in script editor. we would need to copy LIB/JAR files to hot deploy.
Hope this helps.
Thanks,
Rajesh K Singh