You've probably all sussed this out, but it took me a while to work out how to upgrade the version of Joomla 1.6 from inside the Administrator. I'll probably forget this next time so here's a record.

In Help->Joomla Help, there's a link Latest Version Check which (of course) tells you if you need to upgrade.

Select that link and you get some upgrade advice. If you click on Upgrading 1.6 from an existing 1.6x version, you get a detailed description of how to upgrade, which is . . .

1/ Go to Extensions->Extension Manager->Update;
2/ Click Purge Cache (in one case I found this necessary in another case, not);
3/ Click Find Updates;
4/ Select the Joomla component and click Update;
5/ The version is comfirmed at the bottom of all Admin pages.