What is the complete upgrade path for Mac OS X version 10.7? I went to the Apple website, and they only talk about the upgrade to 10.7 from its previous version, 10.6.x. (and I know 10.8 is coming out soon). 

I am the new tech who tries to support a small number of Mac users in my office, and although they all want to upgrade to 10.7, I know they have different machines with different specs that they do not all run the version 10.6.x of Mac OS X. Do I have to upgrade successively to each version of the OS, up to 10.7, or can I get them all to the latest version in one step (given that their hardware will support it)? 

Also, are the OS upgrades reliable, or is there a history of data loss when performing such an upgrade? Is there an upgrade map, along with models of Macs that I can look at? On the Apple website, they talk about upgrading from 10.6 to 10.7, but nothing for prior versions.

Thanks :-)
For Mac OS X Lion 10.7, you need to have Snow Leopard (10.6) installed and updated to have the Mac App Store. So yes, if you had a computer still on Leopard 10.5, you would first have to install Snow Leopard, update it to get the Mac App Store update, and then install Lion from the App Store.

You mentioned:


  I know 10.8 is coming out soon).


It's coming out tomorrow! :)
Which is great, considering that Mountain Lion 10.8 allows Snow Leopard 10.6 and higher Macs to upgrade directly! 

I've never had any problems upgrading an OS, although I usually run a backup before just in case (and it's a good idea).

I can't find an official Apple article for upgrading from Leopard 10.5, but I'll edit this post if I do.  I would assume that it is as simple as following the directions given when inserting a Snow Leopard install disk.