Hi @HalaAtef,
Normally the latest version should be the more stable version.
Also, new fixes are being ported to another branches (for example, a fix on 2.2.x will be ported to 2.1.x.
But maybe you find a new bug (even Magento1 gets Security Patches after 10 years). In that case you can search for more information here (at the forums) or maybe you can report your issue here: https://github.com/magento/magento2/issues