Tax forms Belgium

@me
"you can logon with your "Belgian E-ID"
Which part of 'I left Belgium last year' in the question did you not read?

"Of course, only a few people are still using the very old fashioned paper based forms"
You obviously know something that the taxman doesn't know. The reality is that more than 50% of tax declarations are done on the very old fashioned paper based forms.
How many people do you think do NOT own a computer?
How many people do you think who DO own a computer do NOT have internet access?
What about the older people who want to do what they are familiar with rather than using a system which, if they get it wrong, could cost them a lot of money?
My wife does our form. She is a university professor and still prefers the old fashioned way so that she can take her time and double check that there are no mistakes.