Not allowed to upgrade with apt-get dist upgrade?

Hi,

My version of linuxcnc is:
This is fresh installation and I'm about to do my first ever testing of 2 stepping motors with easy driver 44. I installed my linuxcnc to HD over 6 months ago and today I did
But then on linuxcnc.org homepage I saw this note at the end:

Note: Do Not upgrade the Linux operating system from the installed version as it will prevent LinuxCNC from working as a specific kernel is required.

Can anyone explain this? Is it wrong to upgrade this way? I want to make sure I have my setup right before start plugging cables and electrics.

you don't want to upgrade to a newer version of the distribution.
eg don't upgrade 10.04 to 10.06
looks like you are using Debian Wheezy so stick with Wheezy.

other upgrades are usually fine, with the caveat that kernel upgrades usually make themselves the preferred kernel to load,
so you might have to manually select the right kernel or otherwise fix that problem.

Chris M