power suply upgrade? display card iupgrade? SATA cable upgrade?

You can determine the operating system version by pressing the About screen.  

The current version is 2.1. 

It's a very easy upgrade, you navigate to the Downloads page on the ETC website, fill in the form info and you will get a file to download.  Make sure you select the Console version, not the Off-Line Editor, unless you want that.  The file will download as a WinZip, you extract it on the PC/Mac and will get an executable file that you transfer to a USB drive.  Having installed that USB on the USB drive slot, boot the console.  When the Ion is booting, interrupt the boot process (press the button that has the countdown), navigate to the Update section.  The console will have recognized the USB drive and will prompt you to start the installation.  It's all painless from there.  

Besides a ton of improvements to the operating system over the assorted versions, having the latest OS makes it easier for ETC tech. support to help you with problems, so it's recommended to keep the console up-to-date.

As to hardware, there's nothing to update.  As Hans has indicated, unless the console has exhibited problems, they don't routinely do swap out of hardware. The only change would be to order (free) the new keycaps (if you have the old model), that has the Shift key and which improves the user interaction.  The keycap order is also done on the ETC website and is as well, an easy upgrade.   

As to "channel" upgrades ?, the console has 10,000 "Console Channels" which is the maximum available throughout the Eos family line.  Possibly you are thinking about DMX addresses, which can be upgraded as needed to expand the number of addresses available.  But do you need to ?.  The basic model Ion has 1024 DMX addresses and unless you are running a big rig with a lot of LED's and/or moving lights, you may have plenty already.  

You can determine the operating system version by pressing the About screen.  

The current version is 2.1. 

It's a very easy upgrade, you navigate to the Downloads page on the ETC website, fill in the form info and you will get a file to download.  Make sure you select the Console version, not the Off-Line Editor, unless you want that.  The file will download as a WinZip, you extract it on the PC/Mac and will get an executable file that you transfer to a USB drive.  Having installed that USB on the USB drive slot, boot the console.  When the Ion is booting, interrupt the boot process (press the button that has the countdown), navigate to the Update section.  The console will have recognized the USB drive and will prompt you to start the installation.  It's all painless from there.  

Besides a ton of improvements to the operating system over the assorted versions, having the latest OS makes it easier for ETC tech. support to help you with problems, so it's recommended to keep the console up-to-date.

As to hardware, there's nothing to update.  As Hans has indicated, unless the console has exhibited problems, they don't routinely do swap out of hardware. The only change would be to order (free) the new keycaps (if you have the old model), that has the Shift key and which improves the user interaction.  The keycap order is also done on the ETC website and is as well, an easy upgrade.   

As to "channel" upgrades ?, the console has 10,000 "Console Channels" which is the maximum available throughout the Eos family line.  Possibly you are thinking about DMX addresses, which can be upgraded as needed to expand the number of addresses available.  But do you need to ?.  The basic model Ion has 1024 DMX addresses and unless you are running a big rig with a lot of LED's and/or moving lights, you may have plenty already.