Conversion Error - no support available

At some recent point, LibreOffice changed the standard for .odt files. The current version of LibreOffice .odt files cannot be read by OOReader. Files created or modified in April 2016 are fine, but if the file was saved after that, OOReader shows "conversion error". Tried to report this to the ooreader email address shown in iTunes, but that account is dead. OOReader worked well, when it worked, but apparently its dead now.

telserv about OOReader, v5.0.3