Finding out your Kodi version
You can find out what version of Kodi you are running under the System Info section. This is usually available via the Settings menu, but can vary if you are using a different skin.
You can also find out your Kodi version via the command line:
grep Kodi .kodi/temp/kodi.log | head -3
Finding out your OSMC version
You can find out what version of OSMC you are running via 'My OSMC'. This can be found on the home menu if you are using the OSMC skin or the Settings menu if you are using the Confluence skin. If you are using another skin, you will be able to find 'My OSMC' via the Programs menu.
You can also check your OSMC version via the command line:
grep VERSION_ID /etc/os-release
You can learn more about keeping OSMC and Kodi up to date here.