Hi
i have managed to open .xls files form mail app by adding document type to the project build and set the Types field to \"com.microsoft.excel.xls\" (see screen shot).
I solved that by defining custom UTI as follows. Try to add these definitions into your info.plist. It works as expected.
UTExportedTypeDeclarations
UTTypeDescription
XLSX input table document
UTTypeTagSpecification
public.filename-extension
xlsx
public.mime-type
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
UTTypeConformsTo
public.data
UTTypeIdentifier
com.mydomain.myapplication.xlsx
....
CFBundleDocumentTypes
CFBundleTypeName
XLSX input table document
LSHandlerRank
Owner
CFBundleTypeRole
Editor
LSItemContentTypes
com.mydomain.myapplication.xlsx