Trisquel follows the fixed (LTS) release model. But this doesn't mean that
you have to use whatever is in the official repository. You can download and
install the latest version of LibreOffice manually.
To install LibreOffice manually, just download the tarball, extract it,
change the directory (cd) and then run # dpkg -i ./*deb
In a fixed-release distribution, everything is old except the browser. In a
rolling-release distribution, everything is new except the browser (Debian
testing still uses Firefox ESR 52).
