Why is system upgrade showing unstable version when upgrading in backend?

[Fischamhaken]

Hi Magento Team,

testing an upgrade from 2.1.7 to 2.1.9 and further, I was wondering why Magento shows the versions from 2.1.10 to 2.1.12 as "unstable versions" ?!
what does that mean - should one upgrade or not to this versions?

Cheers,
Stefan

[AmagArtwork]

I'd like to know why they're showing "unstable" as well. Especially since 2.1.12 says it has enhanced security.

I have modules that prevent me from going to the 2.2 version.