According to Repology, the current upstream release is 1.16.6. Please bump.
According to GitHub, Version 16.6.5 is the latest release (which is marked as such). Additionally it is the latest version with a prebuild rpm and appimage.
For Version 16.6.6 there are only source-files available which do not compile.
Therefore I assume that 16.6.6 is a kind of test release.