This product allows you to add on certain extensions according to your need. (moneyhelpforchristians.com)
See «Resources >> Office» for the top FOSS office suites that support ODT (and DOC [X]-RRB- format, though certain extensions are necessary for layout and ePUB work. (ndauthorservices.com)
With Firefox Quantum, the complaint de jour is that certain extensions do not work anymore. (howtogeek.com)