when I try placing the MK 2 Ion cannon I get this message "outdated techknowledgy has cause an explosion hopefully no one was hurt." the MK 1 I am able to place and use normally so I am wondering if I am doing something wrong or if this is a bug?

yes you are doing something wrong, this is also stated in the text. dont mix mk1 with mk2
can be read in FAQ

In your case, research into the Mk2 technology upgrade has not yet been completed.

but the first time I tried to place it I had not even built a MK 1 yet I went straight to MK 2

you dont need to build Mk1 if you can wait for Mk2

so why did it give the same issue when I did? to specify I tried to place the MK 2 first got that message then tried the MK 1 so I thought I might be able to place the MK 2 now but same issue

To place a Mk2 research the Mk2 upgrade. I have already said that.

Hi, I have a question about this update
if, for example, I launch ion cannons into orbit around planet A
unlock the MKII
and then go to a new planet
can I launch new ion cannons?

Why you wriiting in a closed thread?? New question, new thread please.
Short answer: Yes. Ion cannons are always installed in the orbit of the current planet and remain there even if you move your platform.