I think the guidelines should be updated to let the reader know that they should include the version of Tableau they're using. Or maybe have a radio button or drop-down control of the versions?
Because of the differences between 7 and 8 I think this distinction will be necessary for both question and answer posts, Server and Desktop, especially during the roll-out of version 8 as not everyone will perform the upgrade (until we get Server 8 running we won't be upgrading). If a control is used to select the version then it should also be editable in case the author didn't select the correct one.
Good idea Toby! I'll add it to the guidelines for now and see what we can do about having a drop down control of versions.