Patch 8193.13 came out one week ago, and I just noticed that all the files in the NWN EE tab in my library are marked with this version number now, too, even though the changelog does not mention it and (of course) there was no notification about it here.

Also, some reports from users on the Steam forums suggest that this stable patch might not be so stable after all, so before installing .13, make sure you keep the backup of the older version, if you made one, just in case.