OpenOffice is 15 or so years behind but LibreOffice isn't. LibreOffice forked from OpenOffice in 2011 and the vast majority of volunteers working on it left the OpenOffice project and kept working on LibreOffice.

Anyone still using OpenOffice probably doesn't realize they would likely be much better off using LibreOffice instead.

OpenOffice doesn't support docx or xlsx but LibreOffice supports them much better.

Or at least a decade behind, which should be surprising given that it hasn’t been actively developed in about a decade.

Honestly, I hadn't used Microsoft Office in 15 years, and it somehow went 20 years backwards in that time.