The last Opus library release was v1.3.1 as a bug-fix release all the way back in April 2019... Fast forward to today, Opus 1.4 is now available although it's not too significant of a release.
Most noticeable with Opus 1.4 is now having Meson build system support. Meson has become increasingly popular with open-source projects the past few years for its speedy build support with Ninja, much better cross-platform compatibility than Autotools, and other modern features.
Opus 1.4 also features improved tuning of the in-band FEC (LBRR), a new option to turn on FEC, and improved tuning and fixes to the DTX code.
Downloads and more details on today's Opus 1.4 release via the project's GitHub .