Fix#4280, an issue with many problems; this is the last one (PR #4281 and PR #4677 dealt with other aspects of the problem). New releases of Excel allow representing TRUE/FALSE as a checked/unchecked checkbox. This requires a change to Styles, as expected. But Excel has implemented it in such a manner that changes are also required to Content_Types and workbook.xml.rels; and a new xml file propertyFeatureBag is also required. Seems like a lot of work for such a small change. A new property is added to Style, but only Xlsx Reader and Writer support it; no other format does.
oleibman